Exoprosopa busiris

Greathead, D. J., 2001, A study of the Exoprosopa busiris (Jaennicke) group of Bezzi (1924) in tropical Africa (Diptera: Bombyliidae), Journal of Natural History 35 (1), pp. 127-147 : 128-131

The Exoprosopa busiris -group

(Figures 1±18)

The species included in this group have the following characters in common. None of these are exclusive to the group but together they serve to delimit the species included in this study.

Diagnosis

Large to very large, 10±22 mm in length. Body black, usually entire face but at least margins of buccal cavity yellowish; paler areas also present on pleura and abdominal sterna, occasionally also on abdominal terga. Scutellum reddish. Head with facial cone conical but blunt. Antenna with ®rst ¯agellomere elongate conical, second not longer than pedicel. Legs black to reddish or brown. Fore tibiae smooth; fore tarsi slender, as long as fore coxae. Wing (®gures 1±8) large, at least as long as body, often longer. Cross-vein m±m short, straight and oblique to wing margin. Discal cell thus truncate, usually broadest at end and narrowest opposite cross-vein r±m. Cell r narrowed towards wing margin but always open. Fore margin with a 5

brown infuscation and at least traces of spots on cross-veins, sometimes veins bordered brown or entire wing membrane infused brown, then spots absent and

)

8

(

;

schmidtii

.

E

)

7

(

; selenops

.

E

)

6

(

;

brevinasis

.

E

)

5

(

; magnipennis .

(

4

.

E

)

decastroi

.; atrinasis E

.

E

)

3

(

;

luteicosta

.

E

)

2

(

; busiris

.

E

)

1 (

: Wings

.

8

±

1

IGS

F

FIGS 15±18. Spermatheca: (15) E. luteicosta ; (16) E. selenops ; (17) E. W ssicornis; (18) E. linearis .

centres of cells tending to be paler. Abdomen ¯attened, usually broad, ovate but narrower, almost parallel sided in species with fully infuscated wings. Vestiture with hair on head black, scales on frons, face and occiput gleaming silvery or yellowish. Hair on thorax and ®rst abdominal tergum usually ochreous yellow, sometimes darker yellow or orange. Abdomen with a pattern of black and white scale bands on terga, usually distinct on most terga but at least narrow bands of white scales visible on some segments in well preserved specimens. Macrochetae on legs black, scales usually black but sometimes with more or less extensive ochreous scales. Male genitalia (®gures 9±14) large and with a long tongue-shape d epiphallus. Spermatheca (®gures 15±17) with a small globular or ovoid terminal bulb followed by a narrow elongate section separated from a thin-walled swelling just distal to the sperm pump.

The species in this group can be distinguished on the colour and pattern of the vestiture and of the wing infuscation. The male genitalia are little diOEerent from other species groups but the form of the spermathecal bulbs appears to be characteristic of the group. Some species of the E. dimidiata -group have a diOEuse wing infuscation but they are at once separated from the E. luteicosta -group on the spermatheca which has a globular pigmented bulb separated from the sperm pump only by a second thin walled, transparent globular section. These species also have a less uniformly banded abdomen, having at most complete bands on the second, third, sixth and seventh terga and the other segments without white scales or with only a pair of lateral spots.

The species under consideration fall into three series, one resembling E. luteicosta - atrinasis with a clear wing membrane, the second comprising smaller species with a faintly tinged wing membrane resembling E. W ssicornis-erronea and the third resembling E. tabanoides - schmidtii with the wing membrane more or less completely infuscated and with less clearly de®ned and contrasting banding of the abdomen.