The wing venation is quite distinctive: the radial segment R2+3 is strongly contorted into an "S"-shape, and is connected (at first sinus of the "S") by a cross-vein to R4 (see wing diagram from the MND(1) here
A key for distinguishing Dipalta
from the related genus Neodiplocampta
appears on pg. 323 of Hull & Martin (1974)
, with figures of wing, head, and antenna for D. serpentina figures appear on pg. 338
. Hull & Martin (1974) give no description of D. serpentina
. For the detailed original 1877 description by Osten-Sacken, and one written shortly thereafter by Coquillett, see "Print References" below.
Widely distributed in Nearctic: Mexico, U.S. (AZ, ARK, CA - type locality, CO, FL, GA, ID, IL, IN, IA, KS, KY, ME, MD, MA, MI, MN, MO, MT, NE, NV, NM, NC, ND, OH, OK, OR, SD, TN, TX, UT, WA, WI, WY)
also Neotropical: Cuba, Guatemala, Honduras.
From Cole & Schlinger(2)
: "In Calif. species is most abundant in August and September"
Larvae are parasitoids of pupae, and perhaps also larvae, of antlions (Myrmeleontidae).
For many years it was stated that Dipalta
were parasitoids of antlion larvae
...for instance, in the following quote from Cole & Schlinger(2)
"A specimen from Lake Co., Calif., was bred from a myrmeliodid larva; the fly pupa emerged from the globular, sand-encrusted cocoon of the ant lion on August 10, 1933, the adult emerged on September 17, 1933 (MacSwain)"
However, the 1989 paper by Leech & Leech
demonstrated a clear instance of Dipalta serpentina
parasitizing the pupal
stage of an antlion (rather than the larval
stage). D. serpentina
might also parasitizes antlion larvae
, though it seems to be in question (earlier observers may have not observed carefully enough to distinguish between larval & pupal parasitism).
Hull, F. M., & W. C. Martin. 1974. The genus Neodiplocampla
Curran and related bee flies (Diptera: Bombyliidae). Proc. ent. Soc. Wash. 76:322-346. (Read online
Osten-Sacken, C. R. (1877). Western Diptera. Bull. U.S. Geological and Geographical Survey, Vol 3. pp. 236 (Read online
Coquillett, D. W. (1887). Monograph of the species belonging to the genus Anthrax
from America north of Mexico. Proc. Amer. Ent. Soc. Phil., Vol 14 (Read online