Forgotten Foto Friday: Eudioctria sp.

Eudioctria sp. | Shaw Nature Reserve, Gray Summit, Missouri

In keeping with my recent theme featuring insects from Shaw Nature Reserve, I present here a long-forgotten photograph that I took back in May 2009.  In fact, not only was this photo taken on the maiden voyage of my Canon dSLR setup, but it is the very first photograph of an insect that I took with the camera—image #19 (1-18 were the initial test shots and a few immediately discarded photos).  It won’t win any awards, but it’s not a bad photo, and the fact that I immediately began attempting shots with the lens dialed all the way up to 1:1 shows I had no qualms about going for broke.

As best I can tell, this is a member of the robber fly genus Eudioctria in the subfamily Stenopogoninae.  Species in this genus are among the tiniest of North American robber flies,  measuring only 6–8 mm in length (compare this with the spectacular 35–40 mm length of North America’s largest robber fly).  They superficially resemble species of the unrelated genus Cerotainia (subfamily Laphriinae) but lack the extra-long antennae. According to Norman Lavers (The Robber Flies of Crowley’s Ridge, Arkansas), Eudioctria can also be distinguished behaviorally, as it prefers flat leaves at the top of small shrubs, while Cerotainia tends to perch on twig-ends.  Eudioctria is primarily a western U.S. genus, although four of its 14 species (albius, brevis, propinqua, tibialis) occur in the eastern states (Adisoemarto and Wood 1975).  I can’t possibly determine which of those four species this individual represents, as to do so requires examination of facial gibbosities and judgements about the degree to which various body parts are pollinose(?)—perhaps I should stick with beetles!


Adisoemarto, S. and D. M. Wood.  1975.  The Nearctic species of Dioctria and six related genera (Diptera, Asilidae).  Questiones Entomologica 11:505–576.

Copyright © Ted C. MacRae 2011

The marvelously monstrous Microstylum morosum

A few weeks ago, while waiting to begin my nocturnal hunt for the Great Plains giant tiger beetle (Amblycheila cylindriformis) in northwestern Oklahoma, I spent the daytime atop one of the red flat-topped mesas that meander through the area in nearby Gloss Mountain State Park.  Although my trip was all about seeing this giant of a tiger beetle in the wild for the first time (I could hardly wait for dusk to begin my search), I found enough splendid insects of other types atop the mesa to occupy my interest until that time.  One of these was the still-robust population of the Swift Tiger Beetle (Cylindera celeripes) that I discovered last summer and delighted in photographing yet again, while another was North America’s largest robber flyMicrostylum morosum!  I had just finished photographing one of the tiger beetles near the edge of the mesa when I turned and saw one of these impressively large flies sitting calmly on the ground nearby.

I first encountered this species last year in southwestern Missouri (a new state record!), so there was no question about its identity.  I also remembered how skittish they were and how difficult it was to get even the two mediocre photographs that I included in the resultant post.  Expecting the same, I kept my eye on the ground-sitter while preparing the camera and approached it with extreme caution.  To my surprise, it showed no sign of being alarmed or wanting to take flight.  I crouched down low and marveled at its monstrous impressiveness as I took frame after ever closer frame – eventually zeroing in on the head and its stunningly magnificent emerald-green eyes.

Satisfied that somewhere in the dozen and a half frames that I shot was at least one or two winners, I sat up and probed towards it with my finger to see how quickly it took flight.  It just sat there tenaciously until my touch caused it to finally take wing.  Winds were gusty atop the mesa, which may have accounted for its cooperativeness.  Standing up, I noted a few scattered eastern redcedars (Juniperus virginiana) in the mixed-grass prairie at the highest point of the mesa.  I recalled that robber flies are fond of “hilltopping” – a mating strategy whereby males fly to the highest point in their immediate landscape to defend a small territory or perch that provides a good vantage for spotting females and competing males (see Hilltopping by Eric Eaton at Bug Eric for a good discussion about this) – and my own experience with this species in Missouri and the way it tended to perch in the trees scattered across the upper part of the rocky, dolomite glade where I found them.  I wandered up to the redcedars, and as soon as I came close enough to one of them I saw another individual take flight – looking like some super-sized mosquito with it’s long legs spread wide as it clumsily flew to another tree.  As it turned out, I saw a number of individuals and mating pairs perching and flying among the trees on top of the mesa, each more spectacular than the previous.

Until recently, Microstylum morosum was considered a Texas-endemic.  However, Beckemeyer and Carlton (2000) documented this species to be much more broadly distributed in the southern Great Plains (from Texas up into Oklahoma and Kansas and west into New Mexico, Arizona, and Colorado), and Warriner (2004) recorded it shortly afterwards in Arkansas.  Although the species apparently occurs throughout Oklahoma (Beckemeyer and Carlton recorded from 13 counties across the state), my observation of it in Major County does seem to represent a new county record for the species.  There is another U.S. species in the genus, M. galactodes, and it has also been recorded from Oklahoma (the closest record is in nearby Woodward County).  However, it is easily distinguished by its generally smaller size, milky white wing membranes, reddish-brown body, and head and thoracic dorsum evenly covered with whitish pruinescence, while M. morosum has the wings and body black to brown and thoracic pruinescence restricted to the lateral margins (Beckemeyer and Carlton 2000).  I’m not sure I would have recognized that species for what it was had I seen it, but if it is anywhere near as impressive as M. morosum then I hope I have the fortune to find it someday as well.

Photo Details:
Landscape: Canon 50D w/ 17-85mm wide-angle lens (17mm), ISO 100, 1/100 sec, f/10, ambient light. Typical post-processing (levels, unsharp mask).
Insects: Canon 50D w/ 100mm macro lens, ISO 100, 1/250 sec, f/10 (photo 1), f/18 (photo 2), Canon MT-24EX flash (1/4 ratio) w/ Sto-Fen diffusers. Typical post-processing (levels, minor cropping, unsharp mask).


Beckemeyer, R. J. and R. E. Carlton.  2000. Distribution of Microstylum morosum and M. galactoides (Diptera: Asilidae): significant extensions to previously reported ranges.  Entomological News 111(2):84–96.

Warriner, M. D.  2004. First Arkansas record of the robber fly Microstylum morosum (Diptera: Asilidae).  The Southwestern Naturalist 49(1):83–84.

Copyright © Ted C. MacRae 2010

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Me and my buds!

Those of you who have followed this blog for any length of time have seen repeated references to my friends and colleagues, Chris Brown and Rich Thoma. Rich and I have been collecting insects together for almost 25 years now (since shortly after we bothed first moved to the St. Louis area), and Chris has joined us in the fun for the past ten years as well. It is rare when all three of us can get out in the field together – meshing hectic professional and family lives with the sometimes coincident, sometimes divergent insect collecting goals of three fathers can be challenging. Nevertheless, at least once or twice a year we manage to converge on a date and enjoy each other’s company out in the field. I don’t think I’m ever happier than when I’m in the field (well, except when one of my daughter’s nestles into my lap to watch a movie!), and the chance to share that experience with close friends of like interest is especially gratifying.

Chris is quite an accomplished insect photographer himself, having been at it for much longer than I’ve known him and providing me great coaching as I’ve begun testing the waters myself. Recently, he sent me some photos from our 2009 field trips to the lowlands of southeastern Missouri and the Loess Hills of northwestern Missouri. Those were two exciting trips, revealing new localities for Cicindela scutellaris, the discovery of Cylindera celeripes in Missouri, the rediscovery of Ellipsoptera macra, and even a new state record robber fly.  The sharing kind of guy he is, he’s granted me permission to post them here (plus one taken by Rich Thoma).

Rich (left) and Ted scan 2-track through sandy ground in the southeastern lowlands looking for tiger beetles.

Ted and Chris take a break from looking for tiger beetles in a sand prairie relict. Photo by Rich Thoma.

Ted attempts to extract an adult tiger beetle from its daytime burrow in a sand prairie relict.

Ted scans the open sand in a sand prairie relict for adult tiger beetles.

Ted fishes for a tiger beetle larva in a sand prairie relict.

Ted photographing the robber fly, Ospriocerus abdominalis, at Star School Hill Prairie in the Loess Hills of northwest Missouri.

Distant view of Ted (small spot in center) photographing Ospriocerus abdominalis at Star School Hill Prairie.

Copyright © Ted C. MacRae 2009

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North America’s largest robber fly

Female Microstylum morosum perched on fragrant sumac (Rhus aromatica) bush

Female Microstylum morosum perched on fragrant sumac (Rhus aromatica)

A few days ago, I featured Promachus hinei, one of the so-called “giant robber flies” and a common inhabitant of the glades and grasslands that dot Missouri’s largely forested landscape. That individual was seen at Long Bald Glade Natural Area in Caney Mountain Conservation Area, one of the many limestone glades that are a prominent feature of extreme southwestern Missouri’s White River Hills, as it snacked on a small carpenter bee (Ceratina sp.) and posed obligingly for a series of super close-up photographs. Promachus and its congeners are impressively large; however, I would see an even larger robber fly that day. I didn’t know what it was at the time, but I knew that never before had I seen such a magnificent fly, with its large, shimmering, emerald eyes, streamlined body almost devoid of setae (hairs), and ludicrously large size. These monsters were actually quite common at the glade, so I failed to appreciate the significance of what I was seeing as I chased one after another – more intent on securing photographs than specimens. This was not an easy task – they were extremely wary, rarely allowing me to approach within 12 feet no matter how cautiously and slowly I moved. Not one to back down from such a challenge (remember, I stalk tiger beetles), I persisted, traversing the rough, rock-strewn terrain amidst clumps of big bluestem (Andropogon gerardii), Indian grass (Sorghastrum nutans), and fragrant sumac (Rhus aromatica) until, at last, I got within striking distance of the impressive female shown in these photos. Taking flight before I felt assured of a good shot, I followed her repeated long, loping escape flights until I was able to get another few shots and she disappeared for good.

Same individual as in previous photo after flying to another perch.

Same individual as in previous photo after flying to another perch.

It didn’t take long after I returned home to figure out what I had seen, as there is really nothing that can be mistaken for Microstylum morosum, North America’s largest robber fly (Back 1909)¹. At 35–40 mm of length, this individual didn’t quite match the astounding 50-mm upper body length for the species (that’s 2 inches, folks!). Nonetheless, it was an impressive beast indeed! It is not surprising that North America’s largest robber fly should be a species of Microstylum, as it is this same genus that contains the world’s largest robber fly – the aptly named M. magnum from Madagascar, with a body length of 60 mm and an almost preposterous wingspan of up to 84 mm (that’s over 3 inches folks!). I don’t know if any flies exist that are larger than this, but certainly none can be more imposing.  While I’m happy with the photos that I did obtain, I must confess some disappointment that I wasn’t able to get more than these basic lateral profile shots.  Of the several photographs of this species that can be found on the web, this female, photographed by Greg Lavaty of Houston, Texas, is (in my humble opinion) certainly the most stunning.

¹ Puzzled by the use of the prefix “micro” in the genus name – hardly seeming appropriate for such an enormous fly – I asked Eric Fisher (retired, California Department of Food and Agriculture) about the name’s derivation, to which he replied, “The name refers to the quite small ‘stylus’ of the antenna apex; Macquart specifically mentions this character in his 1838 original description of the genus. (This is not a very helpful diagnostic character, as many asilids share this feature…).”

Even more significant than its size, however, was its very occurrence on this glade. Like Ospriocerus abdominalis, which I had seen just a few weeks earlier in the Loess Hills of extreme northwestern Missouri, M. morosum is a denizen of the Great Plains, and also like that species it has until now not been known from Missouri. That’s right – another new state record!  Unlike O. abdominalis, however, the Missouri occurrence of M. morosus represents a significant northeastern extension of its known range.  The species was long considered a Texas endemic until Beckemeyer and Charlton (2000) confirmed its occurrence in southeastern Arizona and documented significant range extensions into Oklahoma, Kansas, extreme southeastern Colorado, and extreme northeastern New Mexico.  Its eastern distributional limit was thought to occur along a north-south line from Douglas County, Kansas to Mayes County, Oklahoma to Brazoria County, Texas; however, Warriner (2004) documented its occurrence some 200 miles east of this line in the blackland prairies of southwestern Arkansas.  The occurrence of M. morosum in the White River Hills of Missouri represents yet another significant eastern extension of its known range – Long Bald Glade lies 185 miles NNE of the collection site in Arkansas and 155 miles ENE of the nearest known record in Mayes County, Oklahoma (Locust Grove), making it the easternmost known locality for this species.

As in Arkansas, where the collection site represents one of the highest quality blackland prairie remants in the state, Long Bald Glade represents a high quality remnant of the limestone glades that once occurrred much more extensively within Missouri’s White River Hills.  Like the blackland prairie of Arkansas, the limestone glades of the White River Hills have been dramatically reduced since EuroAmerican settlement due to land use conversion, and fire suppression and overgrazing of the remaining tracts have resulted in significant woody encroachment – chiefly by eastern red-cedar (Juniperus virginiana) – and loss of vegetational diversity. This has caused dramatic reductions in populations of the many Great Plains plant and animal species that are found here and nowhere else in the state.  Considering the overall distribution of M. morosum, it is unlikely that it occurs more extensively within Missouri than the White River Hills, emphasizing the importance of continued conservation and restoration activities in this unique part of Missouri.  However, since the White River Hills extend into northwestern Arkansas, M. morosum may occur in that part of Arkansas as well as the southwestern part of the state.

I thank Eric Fisher and Herschel Raney for confirming the identity of this species and its status as a new record for Missouri.

Photo details: Canon 100mm macro lens on Canon EOS 50D (manual mode), ISO-100, 1/250 sec, f/10-11, MT-24EX flash 1/2 power through diffuser caps.


Back, E. A. 1909. The robberflies of America, north of Mexico, belonging to the subfamilies Leptograstrinae and Dasypogoninae. Transactions of the American Entomological Society 35:137–400.

Beckemeyer, R. J. and R. E. Carlton.  2000.  Distribution of Microstylum morosum and M. galactoides (Diptera: Asilidae): significant extensions to previously reported ranges.  Entomological News 111(2):84–96.

Warriner, M. D.  2004.  First Arkansas record of the robber fly Microstylum morosum (Diptera: Asilidae).  The Southwestern Naturalist 49(1):83–84.

Copyright © Ted C. MacRae 2009

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Prey bee mine

Promachus hinei preying upon a small carpenter bee

Promachus hinei preying upon a small carpenter bee

Robber flies of the genus Promachus – the so-called “giant robber flies” – are among the more conspicuous and fearless predators seen in Missouri’s glades. Able to capture almost any flying insect regardless of size, this individual – seen at Long Bald Glade Natural Area in Caney Mountain Conservation Area – was found snacking on what, according to my hymenopterist friend Mike Arduser, appears to be a female individual of the genus Ceratina (the so-called small carpenter bees in the family Apidae). Of the three “tiger-striped” (referring to the yellow and black striping of the abdomen) species of Promachus in the eastern U.S. species, P. hinei is the most common in Missouri. It is distinguished from the more southeastern P. rufipes by its reddish versus black femora and from the more northern P. vertebratus by the larger dark areas dorsally on the abdominal segments and distinctly contrasting two-toned legs. Despite their common name and impressive size, however, they are not the largest robber flies that can be seen in these glades…

Photo details: Canon 100mm macro lens on Canon EOS 50D (manual mode), ISO-100, 1/250 sec, f/13, MT-24EX flash 1/4 power through diffuser caps.

Copyright © Ted C. MacRae 2009

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Ospriocerus abdominalis

Photo details: Canon 100mm macro lens on Canon EOS 50D, ISO 100, 1/250 sec, f/14, MT-24EX flash 1/4 power w/ diffuser caps.

Photo details: Canon 100mm macro lens on Canon EOS 50D, ISO 100, 1/250 sec, f/14, MT-24EX flash 1/4 power w/ diffuser caps.

My dipteran digression continues with this photograph of the robber fly, Ospriocerus abdominalis (Diptera: Asilidae).  More than just a pretty picture, this represents yet another apparently new state record that I and my colleague Chris Brown discovered a few weeks ago during our 2-day survey of Missouri’s critically imperiled hilltop prairies in the extreme northwest corner of the state.  Like the previously discussed Cylindera celeripes (swift tiger beetle) and Beameria venosa (a prairie-obligate species of cicada), O. abdominalis has not previously been recorded further east than Nebraska, Kansas, Oklahoma and Texas. This large fly is a grassland denizen that ranges over western North America and into Mexico (Cannings 1998, as Ospriocerus aeacus). It is somewhat suggestive of a mydas fly, although its short antennae immediately identify it as a robber fly (mydas flies have elongate clubbed antennae).  It also reminds me of the magnificent western robber fly Wyliea mydas by its mimetic, wasp-like coloration – presumably modeled after spider wasps of the genus Pepsis and Hemipepsis (Hymenoptera: Pompilidae) – but is distinguished by its black body and wings with red dorsal coloration on the abdomen (W. mydas has the abdomen wholly black and the wings red).  While not quite as handsome as W. mydas, it is impressive nonetheless.

The dry hilltop prairie remnants in which O. abdominalis, B. venosa, and C. celeripes were found are associated with the Loess Hills, a unique landform along the western edge of Iowa that reaches its southern terminus in extreme northwest Missouri.  Due to their extreme rarity and vulnerability to woody encroachment and anthropogenic degradation, these remnant habitats are considered one of Missouri’s most critically imperiled natural communities. Only about 50 acres of original habitat remain, and of this only half is in public conservation ownership.  Many of the plants and animals found in these habitats represent hypsithermal relicts that migrated eastward during a dry and warm period after the last ice age and were then “left behind” in pockets of relictual habitat as a return to cooler, wetter conditions forced the main populations back to the west.  More than a dozen plants and two vertebrates occurring in these prairies are listed as species of conservation concern.  As is typically the case, the flora and vertebrate fauna of these remnant habitats have been fairly well characterized, while precious little attention has been given to the vastly more diverse invertebrate fauna.  As we begin to study the insects of these habitats more carefully, we are almost sure to find a great many species that are more typically found further to the west and that live nowhere else in Missouri.  Their continued presence in the state will be wholly dependent upon the critically imperiled habitats in which they live, making conservation and restoration of the remaining loess hilltop prairie remnants in Missouri all the more important.

My thanks to Eric Fisher and Herschel Raney for confirming the identity of O. abdominalis.


Cannings, R. A. 1998. Robber Flies (Insecta: Diptera: Asilidae), in Smith, I. M., and G. G. E. Scudder, eds. Assessment of species diversity in the Montane Cordillera Ecozone. Burlington: Ecological Monitoring and Assessment Network.

Copyright © Ted C. MacRae 2009

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Collection Inventory update

The more observant – and taxonomically inclined – among my readers may have noticed the sidebar item entitled, “T. C. MacRae Collection”. The links within that item lead to Google documents detailing the species in those groups of insects that are represented within my collection. I am primarily a beetle guy, and within that vast taxon I focus mostly on the woodboring beetle groups Buprestidae and Cerambycidae and the tiger beetle family Cicindelidae. As you can see, however, I have inventories for several additional groups, including non-beetle families – a testament to my inability to suppress broad interest in insects as a whole. I don’t claim to be an expert in these other groups of insects, but I do enjoy learning about groups outside my chosen field of expertise. It’s a bit of a ‘throwback’ attitude – insect taxonomists of the 19th and early 20th centuries commonly studied multiple families or even orders of insects. This broad approach has largely disappeared in the past 50 years, as taxonomists increasingly have been forced to become narrowly focused on a single insect taxon. I can maintain this broad approach because, while I am a professional entomologist, I am a taxonomist only by avocation. My research is conducted at my own discretion and doesn’t rely on securing grants or fulfilling a departmental mission. Rather, it is directed only by what I find interesting and can reasonably afford in terms of time and expense.

The purpose of this update is twofold – to call attention to two recent additions to the list of inventories, and to explain how the inventories are constructed in the event that some future reader will want to utilize them for reference. In the past two weeks, I’ve received back material accumulated over the years in the families Mutillidae (velvet ants) and Asilidae (robber flies). This material had been sent to experts for identification – doctoral candidate Kevin Williams (Utah State University) graciously provided IDs for the velvet ants, while worldwide asilid expert Dr. Eric Fisher (California Department of Food and Agriculture) kindly identified the robber flies. For each of these groups, an inventory was constructed in which the species represented by my material are listed in the context of the group’s currently accepted higher classification. In each case, higher taxa not represented in my collection are indicated by lighter gray text. A similar approach has been used, to varying degrees, in the other listed inventories. The biggest one, Buprestoidea, represents the bulk of my collection, listing almost 1,500 species from around the world. In this case, not only is the complete higher classification indicated, but all currently recognized world genera are also listed, as well as all known North American species. Again, taxa not represented in my collection are indicated by lighter gray text. Similar inventories have been constructed for Cerambycidae and Cicindelidae, but in these cases the inclusion of taxa missing from my collection is limited to those occurring in North America – their combined worldwide fauna is simply too large for me to concern myself with, given my primary focus on the worldwide buprestoid fauna.

Regarding the Buprestoidea, Cerambycidae, and Cicindelidae – these are my chosen groups of interest in which I am actively building North American representation (worldwide for Buprestoidea). If anyone can provide specimens representing taxa not in my collection, please contact me directly. I am more than happy to exchange for such material. As for the other groups, they are primarily ‘just for fun’ – I collect them when convenient because they are interesting, but more importantly to make them available to others who might have a research interest in them. If anyone working in these groups sees species listed that are of interest to your research, please feel free to contact me for a loan or exchange. I have material in many additional groups not yet listed – inventories will be posted as they become available. If you have interest in a group not listed, please contact me and I’ll let you know what material I have available for loan/exchange.