Sound Ideas: Coneheads

by Carl Strang

When I mention the coneheads to people unfamiliar with singing insects, the response almost always is a smile. I have to agree: one reason why the slightly musical conehead is my favorite singing insect (at the moment) is that name. Our coneheads are all katydids in genus Neoconocephalus. I have been fortunate to spend some time in the field with Gideon Ney, a Ph.D. student at the University of Missouri who is working out of a lab led by Johannes Schul that has done a lot of work with the evolution of that group. Thanks to Gideon I am aware of two species of coneheads that are not supposed to occur as far north as the Chicago region, but turn out to be at least locally common. Today I share recordings of the 6 documented species in the region. Warning: these are not delightfully musical or even (despite the name mentioned above) slightly so. We’ll ease into it with one that is somewhat pleasant to hear: the sword-bearing conehead. Its song:

That recording was made in a grassy upland meadow, typical habitat for the species, but close enough to the edge of the woods that a few common true katydids came through loud and clear. The conehead’s song is the continuous string of rasping ticks or brief buzzes. It has been compared to the sound of a sewing machine or a distant steam locomotive.

The sword-bearing conehead is named for the very long, straight ovipositor on the female.

The sword-bearing conehead is named for the very long, straight ovipositor on the female.

The next species also has a discontinuous song. The slightly musical conehead was given that name because W.T. Davis, who described it, thought it was not very loud (though he later changed his mind on that point).

The rasping sounds are easy for me to hear even with my older ears. This is a wetland species, and the males typically sing in unison.

The coneheads are named for the structure on the tip of the head, especially prominent in the slightly musical conehead.

The coneheads are named for the structure on the tip of the head, especially prominent in the slightly musical conehead.

Another species with an interrupted song is the Nebraska conehead.

The buzzes are not as rough as in the previous species, and will be heard in bushy undergrowth of woodlands, or sometimes bushes out in fields. In the southern part of the Chicago region, where the species is more common, the males sometimes sing in unison as well.

Male coneheads often sing head down. It has been speculated that the cone helps them penetrate the vegetation beneath when they are disturbed and drop to hide. Nebraska coneheads have medium sized, all black cone undersides.

Male coneheads often sing head down. It has been speculated that the cone helps them penetrate the vegetation beneath when they are disturbed and drop to hide. Nebraska coneheads have medium sized, all black cone undersides.

The remaining 3 species all have continuous buzzes. Most common region-wide is the round-tipped conehead, a katydid of meadows and roadsides.

Listen for a crackling sound in this continuous buzz.

Here the cone is short, round, and has a small black area near the tip.

Here the cone is short, round, and has a small black area near the tip.

Next is the marsh conehead, which so far has turned up only in the marshes of the Indiana Dunes parks.

The sound resembles that of the round-tipped, but comes from a wetland rather than dry upland habitat.

The cone of the marsh conehead may be all green as in this female, or show variable darkness of color.

The cone of the marsh conehead may be all green as in this female, or show variable darkness of color.

For the grand finale, here is the very loud song of the robust conehead:

This can be so loud as to be painful to the ears. It carries for long distances, as you may imagine, and is easy to hear from a car at any speed.

The robust conehead’s cone is unmarked and proportionately short. Any conehead species can come in green or brown.

The robust conehead’s cone is unmarked and proportionately short. Any conehead species can come in green or brown.

The robust conehead is most abundant in areas with dry sandy soils. Its habitat range is fairly broad, from open woodlands to prairies to corn fields.

There are at least two other species which are supposed to occur in the region, but which I have not found. Perhaps next winter I will have recordings of false robust coneheads and slender coneheads to share.

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Singing Insects Range Extensions

by Carl Strang

My other presentation at Saturday’s Wild Things conference reviewed the range extensions by 8 species of singing insects that have turned up in our region in recent years. I ran through them in the chronological order of their discovery, and then offered some general points.

Broad-winged tree cricket (Oecanthus latipennis)

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Map from the Singing Insects of North America website (SINA), 2012. The record in DuPage County resulted from this study, and was added in 2006. Prior to that the species was not supposed to occur in the Chicago region.

Map from the Singing Insects of North America website (SINA), 2012. The record in DuPage County resulted from this study, and was added in 2006. Prior to that the species was not supposed to occur in the Chicago region.

Original range sources: Hebard 1934  (“Northern limits of distribution are Hilliary and Quincy”), McCafferty & Stein 1976 described it as a central and southern species in Indiana, with Tippecanoe County the northern extent. I found them in DuPage County in 2006, and subsequently learned they are abundant throughout the county. They also have reached the junction of the Wisconsin and Mississippi Rivers in Wisconsin.

Jumping bush cricket (Orocharis saltator)

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Jumping bush cricket SINA map, 2012. The added red line indicates the northern range limit as of 1969, when Tom Walker reviewed the genus.

Jumping bush cricket SINA map, 2012. The added red line indicates the northern range limit as of 1969, when Tom Walker reviewed the genus.

Original range sources: Hebard 1934 (Shawneetown northern limit in Illinois; “should however be found throughout southern Illinois as it is known as far north as central Indiana”). McCafferty & Stein 1976 (“known only from the southern two-thirds of the state” with Tippecanoe County given as the northern limit). They are rapidly expanding in DuPage County, abundant in the southern half and spreading into the northern half with new northern limits found annually. I also have heard them at Indiana Dunes State Park.

Roesel’s katydid (Metrioptera roesellii)

Roesel's s-wing female Purdue b

Roesel’s katydid SINA map, 2012. Prior to work by Scott Namestnik and me, the range was thought to end in northeastern Ohio, with a small disjunct area in northeast Illinois. The red dots indicate our added findings in 2012.

Roesel’s katydid SINA map, 2012. Prior to work by Scott Namestnik and me, the range was thought to end in northeastern Ohio, with a small disjunct area in northeast Illinois. The red dots indicate our added findings in 2012.

Original range sources: Roesel’s katydid is a European species that in North America first was found in two suburbs of Montreal, Quebec (Urquhart and Beaudry 1953, Beaudry 1955), and is thought to have been introduced between 1945 and 1951. Vickery (1965), who summarized this history, reported that the species had spread into New York state and Vermont by 1965, and that the long-winged variants that originally had dominated the Montreal population were diminishing in favor of the short-winged forms typical of the European continent. The Montreal population apparently was by then limited by an indigenous parasitic nematode. Roesel’s reached Ithaca, NY, by 1965 (G.K. Morris, as reported by Shapiro 1995), and Long Island by 1990 (Shapiro 1995). Short-winged forms were dominating the St. John, New Brunswick, population by 2008 (McAlpine 2009), and so had arrived some unknown number of years earlier. Nickle (1984) reported finding them in Pennsylvania by the early 1980’s. Roesel’s katydids were collected in two northeastern Illinois counties in the late 1990’s (Eades and Otte, no date). I found them in north central Indiana in 2007, and subsequently Scott Namestnik and I have found them throughout northern Indiana (as far south as Indianapolis) northeast Illinois, and last year the Lower Peninsula of Michigan. Others have added Ohio, Wisconsin and eastern Iowa.

Round-tipped conehead (N. retusus)

Roesel’s katydid SINA map, 2012. Prior to work by Scott Namestnik and me, the range was thought to end in northeastern Ohio, with a small disjunct area in northeast Illinois. The red dots indicate our added findings in 2012.

 

Round-tipped conehead SINA map, 2012. The added red line indicates the northern extent of the range in Illinois in 1934 and in Indiana in 1976.

Round-tipped conehead SINA map, 2012. The added red line indicates the northern extent of the range in Illinois in 1934 and in Indiana in 1976.

Original range sources: Hebard 1934 (“Urbana is a northern limital point”), and McCafferty and Stein (1976) had none north of Indianapolis, but they are so common in northwest Indiana and northeast Illinois now that this is a well advanced range expansion in the intervening decades. I also heard a single singing individual in a meadow at Wyalusing State Park in Wisconsin in 2007.

Handsome trig (Phyllopalpus pulchellus)

Handsome trig 2b

Handsome trig SINA map, 2012. The northern dot at St. Joseph County, Indiana, is the result of Scott Namestnik’s work.

Handsome trig SINA map, 2012. The northern dot at St. Joseph County, Indiana, is the result of Scott Namestnik’s work.

Original range sources: Hebard 1934 (northern limits given as Marion County in Indiana and Monticello in Illinois; “confined to southern and central Illinois”). McCafferty & Stein 1976 indicated a northern extent in Tippecanoe County. In 2009 Scott Namestnik was posting photos of them from St. Joseph County.

Swamp cicada (Tibicen tibicen)

Swamp cicada 4AU 4b

Original range sources: This species was mentioned by Alexander, Pace and Otte in their (1972) Michigan singing insects paper, but they expressed doubt that it was a breeding species in the state. However, a later paper (Marshall, Cooley, Alexander and Moore 1996) reported finding it in extreme southern MI (intensive searching found it only in the southern portions only of the southern tier of counties. They were not willing to say whether this represented a range extension or the species being missed earlier). I first found it in Marshall County, Indiana, and DuPage County, Illinois, in 2010, but suspected I had heard it earlier. They are scattered across the southern half of DuPage.

Slightly musical conehead (N. exiliscanorus)

Slightly musical Max Wet b

Slightly musical conehead SINA map. This does not yet reflect our finding them in Porter and Marshall Counties, Indiana, in 2012.

Slightly musical conehead SINA map. This does not yet reflect our finding them in Porter and Marshall Counties, Indiana, in 2012.

Original range sources: Hebard 1934 (northern limits indicated as Tower Hill in south central Illinois, and New Harmony in Indiana). McCafferty & Stein 1976 (“In Indiana it is known only from heavy thickets and grasses along the Ohio River”). Gideon Ney, Nathan Harness and I, seeking slender coneheads, found this species at the Indiana Dunes National Lakeshore in 2012, and I found it in Marshall County as well.

Marsh conehead (N. palustris)

Slightly musical conehead SINA map. This does not yet reflect our finding them in Porter and Marshall Counties, Indiana, in 2012.

 

Marsh conehead SINA map. This does not yet reflect our finding them in Porter County, Indiana, in 2012.

Marsh conehead SINA map. This does not yet reflect our finding them in Porter County, Indiana, in 2012.

Original range sources: Hebard 1934 (“Lawrenceville and Carbondale are northern and western limits respectively for palustris…It is probably confined to the southern portions of Indiana and Illinois.”). McCafferty & Stein 1976 reported Tippecanoe County as the northern known extent. Ney, Harness and I found this species to be common at Indiana Dunes National Lakeshore and present in the state park.

General Points

Most of these range extensions are from south to north. Exceptions are Roesel’s katydid (east to west) and the broad-winged tree cricket (spreading south as well, according to SINA coordinator Tom Walker).

I do not know whether any other of these species likewise are spreading south or in other directions.

Some of these are clear range expansions, as they are species which were well known at the time of earlier studies, and now have become abundant beyond the range as then drawn: broad-winged tree cricket, jumping bush cricket, Roesel’s katydid, and round-tipped conehead.

The others have a spottier distribution, or may not have been as well known then, and so might have been missed by earlier researchers: handsome trig, swamp cicada, slightly musical conehead, and marsh conehead.

As for the possible connection between these range extensions and climate change, Gonzalez (2012) mentioned a calculation, based on work in Gonzalez et al. (2010), indicating that the region’s climate has undergone a temperature change equivalent to a southward shift in latitude of 100km in the 20th century. This is consistent with the magnitude of many of these observed range changes.

Recent Mayslake Singers

by Carl Strang

There have been a number of singing insect photo opportunities of late at Mayslake Forest Preserve. The best, just yesterday morning, was the first long-spurred meadow katydid I have found on the preserve. I could hear its quiet song, but it took a while to find it, tucked into a clump of weedy plants a few feet out from the edge of a woodland.

This angle provided just what was needed to confirm the identification, the long spurs on the cerci showing clearly.

Earlier in the week I found a round-tipped conehead singing close to the ground in a tuft of grass.

This is the most abundant coneheaded katydid in DuPage County, the latest of them to mature and the only one that sings in the afternoon as well as at night.

Last weekend, one of the families on my night hike found a narrow-winged tree cricket on the sidewalk after we finished.

The flash washed out its image a little, but the brown cap and narrow wings show clearly in this photo.

Still earlier an Allard’s ground cricket, the most abundant of Mayslake’s ground crickets, paused while crossing a trail.

Unless the autumn is severe, Allard’s will sing well into November.

Numbers of singing insects are dropping, but there still are plenty to hear this season.

Learning to Identify Insect Songs

by Carl Strang

One of the obstacles to a singing insect monitoring program is the large number of various songs that need to be learned for identification. This is not really much different from learning bird songs for breeding bird monitoring, however (except that the total number of species is smaller here). Instead of being daunted by the entire process, it is possible to take the learning process in stages, beginning with the songs that are common and easy to recognize, the ones you have been hearing all along but simply didn’t have the species labels. Here is a list of a dozen suggested species to start with in the first stage: spring field cricket/fall field cricket (their songs are identical), Allard’s and striped ground crickets, snowy tree cricket, common true katydid, black-legged meadow katydid, greater angle-wing, round-tipped conehead, dog day cicada, scissor-grinder cicada, and Linne’s cicada (for more information on these species, try the tags at the head of this post).

Snowy tree cricket, one of the species on the starter list

This list and those that will follow are for northeastern Illinois and northwestern Indiana. There would be substitutions in other parts of the country (I encourage readers elsewhere to make comments here with their own suggestions). Go to reference recordings of these species’ songs, either on-line at the Singing Insects of North America website or through the CD that accompanies the Songs of Insects book. It is not too late this year to hear many of the species on this list on the warmer days, though some are finished or nearly so.

My recommended species list to focus on in the second stage of learning consists of 8 species and groups of species: greenstriped grasshopper, gladiator meadow katydid, Roesel’s katydid ( three species that sing relatively early in the season), and then later, Carolina ground cricket, Say’s trig, sword-bearing conehead, two-spotted/narrow-winged tree crickets (no need to worry yet about separating the two), and the meadow tree cricket group (3-4 species whose songs are essentially identical to the ear and will remain so).

Roesel’s katydid is a species from the second-stage list.

This list of common species either will take you to additional, though still readily available, habitats, or else require a little more of a practiced ear (which practice you got with the first species group). In particular, seek out and spend some time getting familiar with the songs of the Carolina ground cricket and Say’s trig. They need a little more effort to recognize in the field, but once you have them, they will be touchstones for many other species (much as robin songs are for learning bird vocalizations). If you are starting now, you might push the Carolina ground cricket to the first list, as it is one of the few species singing on the cooler days and evenings.

Once you have mastered the second list of species, you are ready for the more subtle distinctions needed to distinguish the songs in the third species list. This includes separating out the song of Linne’s cicada from similar songs by the lyric cicada, and in some areas, swamp and/or northern dusk-singing cicada.

Linne’s cicada

Also, by this point you are ready to distinguish the two-spotted tree cricket song from that of the narrow-winged tree cricket. Also, the broad-winged tree cricket should stand out now from other long-trilling species. In addition, you no doubt have noticed and begun to puzzle out other species that are more idiosyncratic in their distribution or smaller in numbers that you have encountered in your favorite places.

And that brings you to the fourth stage, learning the songs of whatever remaining species may live in the area you wish to monitor. For this you will need a regional guide. In the Chicago region, you can meet this need with the guide I am developing. It is available for free as a .pdf e-mail attachment. Simply request it at my work e-mail address: cstrang@dupageforest.com

As you are learning and listening, pay attention to which songs you can hear clearly, and at what distances, and which are marginal. This will inform the limitations you will need to address or acknowledge in your monitoring.

Houghton Lake

by Carl Strang

A priority site in this year’s singing insect survey work was Houghton Lake, a Nature Conservancy property near my home town of Culver, Indiana. The muck, marl and sand soils potentially support communities including wetland crickets and katydids that I have not yet found. Last week I spent an afternoon and evening walking through the site.

The property, named for this lake, is of particular interest as it hosts a population of rare massassauga rattlesnakes.

There are many smaller wet areas on the site, which is a flat postglacial lake plain. It has great botanical as well as zoological biodiversity.

For the most part I found a long list of familiar, common species.

Black-legged meadow katydids, like this female, are expected in wet areas.

As I walked the lanes I heard crickets singing in the pattern of Say’s trigs, but with a more mechanical or buzzing sound quality. I spent some time searching, because I thought they would prove to be a species I had not seen before. This effort was rewarded.

The handsome trig is one of the more beautiful singing insects in the region. They are tiny, around a quarter inch long.

Another unfamiliar sound was a rhythmic “warg warg warg” coming from a couple wet prairie areas. The song’s rhythm was like that of slightly musical coneheads, but that katydid produces a call with a distinctly buzzing quality. A comparison of recordings led me to the northern mole cricket. The mole cricket’s song is a chirp, but so deep that it is not readily characterized as such. Like the handsome trig, this was a species new to my experience. For future monitoring purposes I was pleased at how far their songs carry, and that at least sometimes they can be heard singing in the mid-afternoon.

A few conehead nymphs turned up in sweep net samples.

These probably will prove to be round-tipped coneheads, which mature later than most of their relatives.

An additional interesting insect was a great blue skimmer.

This was only the third individual of this species I have encountered.

Most of the conservative species I’d hoped to find at Houghton Lake eluded me, but I was only able to see part of the site, and I intend to return.

Swamp Cicada Confirmed

by Carl Strang

Two years ago I was positive that I had heard swamp cicadas at Springbrook Prairie Forest Preserve, and posted about it in this blog. The habitat and song were right. However, I had not seen any of them, failed to hear any when I checked the site last year, and doubts developed as I noticed how percussive are some songs of Linne’s cicada, our most common summer species. On Saturday morning I returned to Springbrook for another try (this cicada is mainly a morning singer). I heard a distant cicada that sounded right, and made my way to a pair of small isolated mulberry trees.

They were in a dry location elevated above the stream that was converted from a straight ditch to a proper meandering configuration a few years ago.

I came in too quickly and the cicada flushed, but he simply flew to a new perch higher in the same tree. He resumed singing, and I was able to get a good binoculars view. The swamp cicada, unlike most of our members of genus Tibicen, is physically distinctive. It is largely black, with some green about the head and brilliant white spots on the sides of the abdomen. I was able to confirm the identification, and brought out the camera.

Not the sharpest photo, but sufficient to document the identification.

As singing cicadas often do, he changed his location slightly every few songs.

Here’s a side view. Note that he has lowered his beak.

I was able to get good recordings of the songs, too. I feel confident now that I can identify this species by song. It is based on a pulsing vibrato like that of Linne’s cicada, but is distinctively percussive. Though some individual Linne’s have a hard quality to their vibrations, it is not as sharp, and the sound quality is different. To my ear, the swamp cicada’s song is reminiscent of a rapidly struck tambourine. You can hear an example at the Songs of Insects website.

The significance of this is that the swamp cicada is not supposed to occur this far north in Illinois, though it does so farther east. The swamp cicada joins other species including the broad-winged tree cricket, jumping bush cricket, and round-tipped conehead as singing insects that have extended their range to the north in recent decades. Note: older references give chloromera as the species name for the swamp cicada, but more recent ones have been calling the species Tibicen tibicen.

Literature Review: Climate Change and Range Shifts

by Carl Strang

Global climate change, like evolution, is a matter of debate among politicians, but not among scientists. At this point it’s a routine matter of measurement and documentation. One example from last year was a study published in Science (Chen, I-Ching, et al. 2011. Rapid range shifts of species associated with high levels of climate warming. Science 333:1024-1026).

They reviewed a variety of terrestrial organisms, including invertebrates, vertebrates and plants, and found that species distributions “have recently shifted to higher elevations at a median rate of 11.0 meters per decade, and to higher latitudes at a median rate of 16.9 kilometers per decade…The distances moved by species are greatest in studies showing the highest levels of warming,…However, individual species vary greatly in their rates of change.” While their data show most species shifting poleward, a few shifted in the opposite direction.

The round-tipped conehead is one of several singing insect species I have been finding with significant northward range shifts in the past 70 years.

The Chen et al. paper will allow me to compare their measurements with rates of expansion I can estimate from the literature and my observations of at least 4 species of crickets, katydids and cicadas. I’m pretty sure the movements of these species will prove to be consistent with their findings.

Seeking Robust Coneheads

by Carl Strang

Last week I began a review of singing insects I expected to find in northeast Illinois but which I haven’t yet encountered. The next species in this series is the robust conehead.

This is the range map for that katydid from the Singing Insects of North America (SINA) website. At the beginning of my study in 2006 I thought that I had found them in DuPage County, but more careful examination of photos and a found-dead specimen revealed that all so far have been round-tipped coneheads.

Like the robust conehead, the round-tipped has a relatively small cone structure at the tip of its head, but it has a larger black area. Also, it is a smaller insect.

The round-tipped conehead provides an example of how things can change over time. Here is its range map from SINA.

Note how the projected range does not quite reach DuPage County. Yet this is a common species here. Either no researcher previously has noted this or, more likely, round-tipped coneheads have expanded their range.

As mentioned last week, the next step in my search is to examine the SINA database for clues. As was the case with prairie meadow katydids, nearly all the Illinois and Indiana records for robust coneheads are from sand areas or from southern locations with which I am unfamiliar. Two exceptional records stand out, however. One is in fact from DuPage County on September 13, 1955. This observation cannot be discounted as it was made by Richard Alexander of the University of Michigan, who did a lot of pioneering research on singing insects in the Great Lakes region.

The other observation which jumped out was from my home town area of Marshall County, Indiana. That county has a lot of sandy soils, though.
I’m not sure what direction to take with this species. By all accounts its song is much louder than that of the round-tipped, so I guess in future years I need to do more nighttime cruising and listening, especially in sand areas.

Seeking Singers

by Carl Strang

The middle of August through September is the peak singing insect season, and on Tuesday I took the first of a scattered series of vacation days to work on a long checklist of targets. I started with searches of the McKee Marsh edge at Blackwell Forest Preserve, and the area around the bridge over the West Branch of the DuPage River at Winfield Mounds Forest Preserve. My main targets were long-tailed and black-sided meadow katydids. I first found those two species in the county last year, and went to these likely locations in hope of finding more. At Blackwell I found mainly black-legged and short-winged meadow katydids, our two most common species in their respective genera. I also saw a few conehead nymphs like this.

Only about an inch long, and lacking wings, these will have to grow fast to complete their development this season. I suspect they are round-tipped coneheads.

After considerable wading through vegetation depressingly dominated by reed canary grass, I finally spotted a female long-tailed meadow katydid. She did not provide a photo op, but I did post some photos last year from another location.

The Winfield Mounds bridge was on the list thanks to my meeting a photographer who had placed a photo of a black-sided meadow katydid on his website. He said he took the picture at the bridge. Again I found a lot of reed canary grass, but dutifully waded in. Again, plenty of black-legs and short-wingeds, but there were scattered others including a female Say’s trig who hopped onto my net.

I didn’t realize how big the females can get, and how they can have long wing extensions reminiscent of a two-spotted tree cricket’s, until I met this individual. She was a good centimeter long.

Shortly after photographing the trig I spotted a black-sided meadow katydid, and so they indeed persist in that area.

Coneheads

by Carl Strang

The singing insect season is drawing to a close, and I have not mentioned one group to which I devoted some attention this season. The coneheaded katydids are a fairly diverse group of relatively large katydids characterized by cone-shaped structures that rise from the tops of their heads.

Nebraska conehead b

This is a Nebraska conehead. Its song consists of loud, shrill buzzes about 1.5 seconds long, with 1-second pauses between. It sings starting at dusk, in habitat that in my experience always has bushes and usually trees. The only location I have found so far with more than 3 or so singing individuals is Parson’s Grove at Danada Forest Preserve. The scattered bushes against the savanna edge seem to be ideal for this species.

There are two common, widely distributed coneheads in DuPage County’s meadows and prairies. The first to start singing, in the second half of July, is the sword-bearing conehead.

Sword-bearing 2b

Its rapidly ticking song has been compared to the sounds of a distant steam engine or a sewing machine. The other common meadow species is the round-tipped conehead.

Round-tipped conehead 3b

As you can see, these katydids look much alike. The round-tipped has a relatively short cone with a small black area at the tip (compare to the longer cone with a nearly all black surface on the Nebraska conehead, above).

Round-tipped conehead 5b

This one is more of a late season species, starting up in the second half of August and continuing through October. Its song to my ear is much like that of the Nebraska conehead, except that it has very long continuous buzzes rather than interrupted ones.

The possibility that I need to clear up is whether the robust conehead also is present. Its song is continuous, like that of the round-tipped, but reportedly is much louder and at a lower pitch. Its similar cone typically lacks the black tip, and body size is larger. I may have heard some of these at night while driving in past years, but so few in 2009 that I will have to hold this possibility for investigation until next year.

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