930 REPORT OF THE HARVARD AFRICAN EXPEDITION 
epistome, and palpi. This pubescence in addition spreads sparsely over the 
posterior margin of the two abdominal segments! and on the lateral margin 
of the last three.” In the key which follows, the palpi are said to be ‘“‘white,”’ 
whereas in typical biguttatus they are described as ‘‘brown’’;? the dorsum of 
the thorax is also said not to possess black spots in the var. croceus, while these 
are said to be present in typical biguttatus. 
It does not appear to me that the varieties wnimaculatus Macquart and 
croceus Surecouf can well be separated from the typical form on the strength of 
the characters used by Surcouf. Moreover, from the published data it is by 
no means clear that these three color forms are geographically segregated, as 
claimed by Surcouf. According to this author, typical biguttatus would be 
found from Khartoum to the Cape, throughout East Africa and also in the 
Congo Basin; the var. wnimaculatus would extend from Dakar to the Chad, 
between 10° and 17° N. lat. and 20° W. and 10° E. long. (Paris Meridian) ; 
the var. croceus has been recorded from the French Sudan, throughout Upper 
Guinea, to the lower Congo and Angola. 
In the females which I have seen from the Belgian Congo, the head, dorsum 
of thorax and scutellum are clothed with silvery white pile and there are no 
black spots on the dorsum; the abdomen is entirely black without spots, the 
extreme margin and lateral corners of the last three segments alone bearing a 
silvery white fringe of hair; the palpi are milky white, except for the extreme 
black tip. The one male from Matadi is black, with slight, grayish brown 
pollinosity on head and thorax; the abdomen with a large yellowish median 
spot on segments three and four; the palpi are brown-black, covered with 
black pile. One could perhaps regard these Congo specimens as belonging to 
the var. croceus Surcouf. 
Tabanus sudanicus ‘‘Cazalbou,” listed by Bezzi (1906, Bull. Soc. Ent. 
Italiana, XX XVII, (1905), p. 240), has apparently never been described. As 
suggested by Surcouf, it was perhaps based upon the var. croceus of T’. biguttatus. 
T. biguttatus appears to be a case of what may be called partial sexual di- 
morphism. The more common form of the female is that with unspotted abdo- 
men, while the common form of the male has a pale, median, hairy spot on the 
third and fourth tergites. Occasionally females are taken with spots similar 
to those of the male; but males with unspotted abdomen are extremely rare. 
In the usual form of the female, the dorsum of the thorax is clothed with white 
pile; occasionally one finds females where this pile is bright golden; such speci- 
mens are very rare in most localities, but in certain districts they are seen more 
often than elsewhere. 
Tabanus xanthomelas Austen 
Tabanus xanthomelas Austen, 1912, Ann. Mag. Nat. Hist., (8) LX, p. 29 (new name for 7. leucaspis 
van der Wulp). 
Tabanus corax Neave, 1915, Bull. Ent. Res. V, p. 308, figs. 18a-b’ and 19; PI. Vin ae 
(2, larva and pupa). Not Tabanus corax Loew, 1863. 7 
1 Which of the abdominal segments is not stated. 
2 In the Monograph (1909), the palpi are said to be “blackish” in biguttatus and “‘vellow”’ in croceus. 
