Synonyms and other taxonomic changes
Williston, 1882 Trans. Conn. Acad. Arts Sci. 4:332
Explanation of Names
The specific epithet refers to the relatively short proboscis of this species (brachy- = "short", and rhynchus = "beak").
Head: The frons is medially dark and grades laterally into a paler hue (i.e. whitish or yellowish). The cheeks are uniformly pale (whitish or yellowish). The 3rd antennal segment is longer than the 2nd. The proboscis is relatively short (i.e. it's tip usually reaches only a bit beyond the 1st antennal segment).
Thorax: Black, with whitish, pollinose (="dust-like"), rectangular markings on the humeri (= anterior corners on dorsum of thorax). There is a whitish-pollinose stripe on the pleuron (= side of the thorax) of uniform width and extending the entire length of the pleuron from between the bases of the fore- and mid-legs to near the upper edge of the thorax. See images below (which also illustrate the pale cheeks):
Legs: The femora and tibiae in P. brachyrhynchus can vary from a vivid reddish to virtually black. The basal half of the tibiae are often paler (yellowish or off-whitish). The tarsi are blackish, and the pulvilli are yellowish.
Abdomen: The abdominal segments are black in base color, typically with a relatively narrow whitish-to-yellowish posterior pollinose band. The first three segments are usually shiny black...beyond that the segments are often duller and sometimes more-widely finely-pollinose. The female theca is relatively small compared to other members of subgenus Pachyconops:
WY to MA, s. to NM and FL (1)
Due to various degrees of intra-species variation, P. brachyrhynchus can sometimes look very similar to P. bulbirostris, P. excisus, and P. weemsi...as well as Physocephala tibialis!
The form of the pleural stripe can separate the first three of these species. Note that the side of the mesothorax is divided by a suture into an upper portion (= the mesopleuron, AKA the anepisternum) and a lower portion (= the sternopleuron, AKA the katepisternum). In P. bulbirostris the pleural stripe is absent (or much-reduced) on the upper-half (= mesopleuron). In P. excisus the pleural stripe spans the entire length of the pleuron: and is typically wider on the lower-half (= sternopleuron); narrower on the upper-half (= mesopleuron). In P. brachyrhynchus, the pleural stripe reaches the top edge of the pleura too...but it is typically more uniform in width throughout.
In addition, note that P. brachyrhynchus (in accord with its specific epithet) has a shorter proboscis than either P. bulbirostris or P. excisus, and also a much smaller theca in females. Moreover, P. excisus (and, sometimes to a lesser extent P. bulbirostris) has a "complete pollinose vertical stripe"...i.e. a stripe along the posterior edge of the vertex consisting of fine, waxy, whitish "dust" that forms an uninterrupted arc along the upper back-edge of the head.
, on the other hand, (besides its generic differences from Physoconops
) has wings with the discal cell completely & uniformly infuscated (= darkened), and the remainder of the wing posterior to the discal cell hyaline (= transparent). No Physoconops
in our area has that particular wing infuscation pattern, although other species of Physocephala
do (e.g. sagittaria
). And of course P. tibialis
can be separated from the other three species under discussion by the characters that distinguish the genera Physoconops
(e.g., see here
Camras, Sidney (1955), "A Review of the New World Flies of the Genus Conops
and Allies (Diptera: Conopidae)", Proc. U. S. Nat. Mus., Vol. 105, pp. 155-187 (Full Text