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Species Physocephala texana
Classification Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Diptera (Flies)
No Taxon ("Acalyptratae")
Superfamily Sciomyzoidea
Family Conopidae (Thick-headed Flies)
Subfamily Conopinae
Genus Physocephala
Species texana (Physocephala texana)
Synonyms and other taxonomic changes Synonymy below from (1), hyperlinks go to original descriptions:
Conops ochreiceps Bigot, 1887, Ann. Soc. Ent. France, 7:39
Physocephala humeralis Van Duzee, 1927, Proc. Calif. Acad. Sci., 16:580
Physocephala humeralis simulans Van Duzee, 1927, Proc. Calif. Acad. Sci., 16:581
Physocephala aurifacies Van Duzee, 1927, Proc. Calif. Acad. Sci., 16:581
Physocephala buccalis Van Duzee, 1927, Proc. Calif. Acad. Sci., 16:582
Physocephala rubida Van Duzee, 1934, Ann. Ent. Soc. Amer., 27:315 Identification A variable species, usually reddish overall, with dorsum of thorax mostly black. Humeri and apical bands of abdominal segments often yellow dusted. Distal tergites of abdomen usually with conspicuous black spots and often yellow dusted.
Upper Head: Vertex usually a reddish-brown which varies in darkness (sometimes yellowish) with a usually darker (sometimes concolorous) red-brown transverse line at the forward edge, tapering into a perpendicular line extending down the middle of the frons...forming a "T-shaped" marking on the frons typical of nearly all nearctic species of Physocephala. In texana, this "T" is relatively thin compared to other species (and, though it can be blackish, is usually reddish-brown). Note, however, that in some forms (e.g. Van Duzee's "P. aurifacies") the vertex can be completely yellowish and concolorous with the frons and face...with no apparent "T-pattern".
Frons and Face: Concolorous, varying from yellowish to white. Facial grooves and keel concolorous with face.
Cheeks: The cheeks are usually a pale yellow at the center, grading into reddish brown at their forward and rear ends. They also can be unicolorous, either yellow or reddish.
Antennae: Antennal ratios are variable between individuals, but typically the 1st antennal segment is nearly equal to (or at least half as long) the 3rd, while the 3rd is about half as long as the 2nd. (In P. burgessi, the 1st antennal segment usually noticeably shorter).
Thorax: Reddish overall, with three black, usually confluent, longitudinal stripes filling most the dorsum...the two lateral stripes starting and extending further back than the central stripe. Humeri often with yellow-dusted dash-like markings, Scutellum red.
Abdomen: Abdominal segments red, often with thin apical bands of yellow dusting, and large black spots on the dorsum of the third tergite and those beyond...which are often covered with a fine yellow dusting.
Wings: Anterior portion dark. Central portion of discal cell hyaline.
Legs: Overall reddish; tibiae and tarsi yellowish (or reddish). Coxa usually blackish...but can be reddish or yellowish. Range British Columbia to Quebec, and south to Mexico (1)
[Note: The range map on pg. 24 of Camras & Hurd (2) indicates a range for P. texana which includes a huge continuous swath of North America from coast to coast, including Canada & Mexico, but excluding the area consisting of southeast Texas, southern Arkansas, and the entire states of Louisiana, Mississippi, Alabama, Georgia, and Florida (i.e. the Gulf states of the southeast US). However, it seems P. texana is principally a western species...currently the easternmost data point on BugGuide is a single post from Illinois.] Life Cycle As with other conopines, adult females of P. texana pounce on adult hymenoptera hosts, pry open their abdominal tergites (using a coordinated action of their theca and hook-like terminalia) to insert an egg in the host. For more details, see discussion under " Life Cycle" on the Physocephala info page. Remarks An extremely variable species, as evidenced by the large number of earlier names that have been synonymized. Perhaps the most commonly encountered form corresponds to Williston's affinis and Van Duzee's humeralis. [Note: Original descriptions of each synonym can be read via links under "Synonyms and other taxonomic changes" near the top of this page.]
Cole (3) mentions that Bohart raised over 100 specimens from a single bembecine wasp nest and discovered enough variation to include all five of Van Duzee's synonymized forms. Bohart gave a detailed discussion of this (2+ pages) where he used Van Duzee's name P. affinis to refer to what is now called P. texana.
Camras & Hurd (2) state that the color of the head varies from a very dark "T" on the front and entirely dark reddish cheeks, to complete absence of any dark pattern on the front and face. See Also Physocephala burgessi is much like P. texana but has a subtly darker "brick red" hue; has a solidly red cheek (i.e. without the yellow spot of P. texana); typically lacks black spots and yellow "dust" on the abdomen; and has a single median black stripe on the thorax. Bohart(1941) discusses in detail ways to distinguish P. texana (there referred to using the synonym P. affinis) and P. burgessi.
The very similar species Physocephala sagittaria and Physocephala marginata are also quite variable...and their more reddish forms can be very difficult to distinguish from P. texana. Moreover, both species co-occur with P. texana in parts of the mid-west, while P. marginata & P. texana can co-occur in the west. The most salient difference is that P. sagittaria & P. marginata have dark facial grooves (4), whereas P. texana has pale facial grooves:
Physoconops fronto differs from P. texana in having an entirely pale frons, and having the 1st posterior cell of the wing entirely hyaline...as well as in characters that distinguish genus Physoconops from genus Physocephala, e.g. having the cross-vein "r-m" near to the middle of the discal cell (rather than well beyond the middle); having hind femora of more uniform thickness; and exhibiting a more conspicuous contrast in color between its black tarsi and yellow claws and pulvilli.
Finally, Physoconops gracilis differs from P. texana in having the characters of Physoconops mentioned above, and also in having the 3rd antennal segment roughly equal in length to the 2nd segment (rather than the 3rd antennal segment having 2/3 the length of the 2nd antennal segment).
Print References Bohart, George E., & J. W. MacSwain (1939). The life history of the sand wasp, Bembix occidentalis beutenmuelleti Fox and its parasites. Bull. So. Calif. Acad. Sci., 38(2):84-97 ( Full Text)
Bohart, George E. (1940). A record of Physocephala affinis Williston as a parasite of adult Bembix comata Parker. Pan-Pacific Entomologist, 16(1):16 ( Full Text)
Bohart, George E. (1941). A review of the genus Physocephala of the western United States (Diptera, Conopidae). Pan-Pacific Entomologist, 17(3):141-144 ( Full Text)
Camras, Sidney (1957). "A review of the New World Physocephala (Diptera: Conopidae)". Ann. Ent. Soc. Am. 50:213-218.
Camras, Sidney (1996). "New information on the New World Physocephala (Diptera: Conopidae)", Entomological News, 107(2): 104-112 ( Full Text)
Camras, Sidney, and Paul D. Hurd, Jr. 1957. The Conopid Flies of California (Diptera). Bulletin of the California Insect Survey. Vol.6, No.2 ( Full Text PDF)
Freeman B.A. (1966) Notes on conopid flies, including insect host, plant and phoretic relationships (Diptera: Conopidae). J. Kans. Ent. Soc. 39: 123-131. ( Full text)
Parsons, C. T. (1948). A Classification of North American Conopidae. Ann. Ent. Soc. Am., Vol. 41, No. 2, pp. 223-246 ( Full Text)
Van Duzee, M. C. (1927). A contribution to our knowledge of the North American Conopidae (Diptera). Proc. Cal. Acad. Sci., Vol. 16, pp. 573-604 ( Full Text...see pg. 579- 583 for Physocephala)
Van Duzee, M. C. (1934). Conopidae from North Dakota and the Rocky Mountain region. Ann. Ent. Soc. Amer., 27:315-323 ( Full Text)
Williston, S. W. (1882). The North American species of Conops. Trans. Conn. Acad. Arts & Sci., 4:325-342 ( Full Text)
Williston, S. W. (1885). North American Conopidae. Trans. Conn. Acad. Arts & Sci., 6:391 ( Full Text) Works Cited | 1. | A Catalog of the Diptera of America North of Mexico
Alan Stone, et al. 1965. United States Department of Agriculture. | |
| 2. | The Conopid Flies of California
Sidney Camras and Paul D. Hurd, Jr. 1957. University of California Press. | |
| 3. | The Flies of Western North America
Frank R. Cole and Evert I. Schlinger. 1969. University of California Press. | |
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