A Tricky Tachinid

At first I didn't know what to think of this fairly large (about 15 mm), long-legged fly found nectaring at Queen Anne's Lace. The wing venation pointed to a Tachinid, or possibly a Flesh Fly or Blow Fly ...

... but I didn't know what to make of the mouth parts. However, it seems that some tachinid flies do indeed have long beaks: this is Ptilodexia sp. and although not uncommon this was my first encounter with this species. The larvae are parasites of scarab beetles.

Tachinids are the second largest family in the order Diptera (a.k.a. flies ... di → two, ptera → wings). Tachinid fly larvae are often parasites of other arthropods, including insects inimical to human interests, making these flies "beneficial" from our viewpoint. A more typical tachinid, Panzeria sp., members of this widespread genus are parasites of various species of moths.

A mating pair of Gymnosoma sp., the larval host species are sheild bugs and stink bugs, and it's thought by some that the adults might be Batesian mimics of larval stinkbugs.

Another Batesian mimic: at first sight I mistook this Cylindromyia sp. for a wasp. This tachinid fly also parasitizes stink bugs.

Archytas sp. larvae feed on various species of moths ...

... whereas Juriniopsis sp. are more selective in their tastes, parasitizing moths of the family Arctiidae (Tiger, Lichen and Wasp moths).

Imitation is the sincerest form of flattery ...

... and for many species it's also a means of ensuring survival. Batesian mimicry is a kind of mimicry where a harmless species has evolved to imitate the warning signals of a stinging, toxic or in other way dangerous species. (This is different than mimesis, where the mimic assumes the colors and/or profile of, for example, a leaf, twig or bark).

Hummingbird moths generally hover while nectaring and are seldom seen sitting as this one is. I'm calling this a Snowberry Clearwing (Hemaris diffinis) but since this is the only image thus far perhaps the name should be left at the genus level. Ventral view(s) would have helped confirm the species. Further reading at BugGuide.Net

This helps. Not the best of pictures since it's hard to aim the camera at a moving target, but the underside of the moth is visible, and it fits the description for Hemaris diffinis. In the field, even while hovering or flying, this clearwing appears smaller and its color is distinctly greenish compared to ...

... the Hummingbird Clearwing Moth (Hemaris thysbe), nectaring at wild bergamot. This moth has red on the dorsal surface of the abdomen and whitish legs (compare to the legs of the moth depicted above).

Ventral and dorsal views of another Hemaris thysbe

Its overall solid blue-black colors, habit of flicking its tinted wings, and quick nervous manner of moving about while nectaring ... everything about the appearance and behaviour of this Chalcosyrphus chalybeus indicated it was a solitary spider wasp. This insect is actually a species of flower fly, of the family Syrphidae, related to the ubiquitous little black-and-yellow striped hover flies commonly encountered in fields and gardens.

Here are a few more insect imposters I've stumbled across on my travels through thickets of thistles, nettles, prickly ash and poison ivy.

A Tachinid fly, Cylindromyia sp.

A female Clematis Clearwing Moth (Alcathoe caudata)

A species of Long-horned Beetle, Clytus ruricola

A fly, Macroceromys terminalis (formerly genus Xylomya). Thanks to David Bree for help with the I.D. on this one.

This small wasp-like robber fly is only about 10 mm long. At first I thought it might be a species of Eudioctria but having done more research on the Internet it seems this is more likely a member of the Laphria sicula/canis/winnemana complex. The first image is a bit out of focus but the long proboscis is quite visible. And it wasn't long before the fly put it to use ... it looks like it has captured a small beetle.

Exoprosopa decora and Systoechus sp.

As its name suggests this fly is indeed decorated. Bee flies are quite wary and it took a good deal of patience to approach closely enough to catch this handsome insect nectaring.

Some bee flies such as Systoechus sp. have a long fearsome looking proboscis but they do not sting ... it serves as a straw. As a rule these flies sip nectar while hovering (to avoid exposing themselves to Ambush Bugs?) and I seldom see them actually alight on a flower.

A Bee flying, some Bee Flies and A Beetle

A bit more on bees, wasps, et al, and their insect imitators. The picture below was a fluke shot ... I happened to catch this Honeybee just as she was launching herself from the goldenrod.

A bee fly, probably a member of the genus Villa.

Another one of our local bee flies: Exoprosopa decora.

Locust Borer (Megacyllene robiniae) ... a beetle impersonating a wasp

To "Bee" or not to "Bee" Part 2: Hymenoptera mimics continued ...

The Great Golden Digger Wasp: a beautiful insect. Despite its size it’s not aggressive and in fact tends to be wary and difficult to approach closely, making it hard to get a good picture. Someday I’ll try to post some more photos of this wasp as the current images don’t do it justice.

The Blue Mud Dauber looks similar to the Steel Blue Cricket Hunter at first glance. The Cricket Hunter can be easily distinguished in the field; it’s a much larger, more robust and active insect.

Sand Wasp … I still haven’t figured out if this is a member of the genus Bembix or Bicyrtes. It’s difficult to pin down (metaphorically speaking) an insect from a photo. A specimen is necessary to study detailed physical attributes, such as wing venation. Based on the wing detail visible I'm leaning toward Bicyrtes. Henceforth a link will be inserted to the Internet resource with the description which best fits the picture at hand.

A lucky shot … I caught this Sand Wasp right at the moment of takeoff.

Sand Loving Wasp

The Tiphiid Wasp bears a strong resemblance to a queen ant ...

This is probably a Mining Bee

Halictid Bee

Wool Carder Bee

Red-Tailed Bumblebee

Moving on to some mimics … a Syrphid Fly

The fly in the next two images is probably a relative of Sphiximorpha sp., and it takes impersonation over the top; this fly even hovers like a wasp and at rest moves its body and flicks its wings in a wasplike manner.

Mimicry is by no means restricted to members of the order Diptera. What I was hoping for at the outset of this photo expedition was a picture of a Mantidfly (family Mantispidae). These insects do an excellent job of imitating a wasp. No luck getting a pic … Mantidflies aren’t all that common in this area.

With its transparent hind wing and yellow abdominal stripe the Peachtree Borer Moth (this one is a female) resembles a wasp at first glance. There are many other moths that make even more convincing hornets or bees.

Several beetle species also do a creditable job of looking like a dinner that might sting. With its brown and yellow pattern the Flower Longhorn Beetle (Typocerus sp.) will hopefully fake out a predator looking for a potential meal.