348 JAS. J. SIMPSON — ENTOMOLOGICAL 



present must remain doubtful. Professor Newstead in a recent paper 

 differentiated between G. morsitans, Westw., and G. siihmorsitans, Newst., on the 

 strength of structural differences in the male genitalia, but further added that 

 these two species could be distinguished by the abdominal markings, as 

 follows : — * 



In G. submorsitans "the transverse black abdominal bands are : — ■ 

 (a) much more clearly and sharply defined ; 

 {h) equally and more narrowly interrupted in the median line on the third. 



fourth, and fifth segments ; 

 (c) slightly rounded medially and suddenly tapering towards the lateral 

 margins. 

 " In G. morsitans the bands are : — 

 (a) not so sharply defined medially ; 



(6) unequally interrupted in the middle line, the space between the two 



diyisions of the band on the third being much greater than the space 



between those of the fifth segment ; and the dark colour gradually 



shading off into the pale colour forming the median line ; 



(c) broadly rounded medially and very gradually tapering towards the 



lateral margins." 



It is noteworthy that the types of this species were obtained at Katagum in 



Northern Nigeria, co-types in Northern Ashanti, and additional specimens 



in Ashanti and at Baro in Northern Nigeria. Numerous specimens from these 



localities are now in the possession of the Entomological Kesearch Committee, 



but although a careful examination of these reveals that the majority of them 



undoubtedly present the abdominal markings ascribed to the species submorsitans, 



many also show the characteristic markings of G. viorsitans, while all 



intermediate gradations may be found. The specimens in the National 



Collection in the British Museum from other West African Colonies also 



emphasise this point. 



Consequently, it is not premature to say that, should this species be distinct, 

 it cannot be separated from G. morsitans by these external characters, nor for 

 the present ax'e any others available. But, on the other hand, we may take 

 account of the male genitalia, which must, as in other groups of insects, be 

 regarded as characters of taxonomic importance. 



Professor Newstead has separated these two species on the form of the 

 "superior claspers," and the distinctions as shown by him, provided they are found 

 to be constant and not linked up by intermediate forms, as in the case of the 

 abdominal markings, certainly justify the establishment of distinct species. 



In order to see if such a grouping were possible, I dissected the male genitalia 

 of a large munber of specimens from both West and East Africa, including 

 specimens from the same localities as those examined by Newstead. This exami- 

 nation revealed the fact that it was possible to divide them into two distinct 

 groups, and further, these groups corresponded with the geographical distribu- 

 tion ; in other words, the submorsitans type of genitalia (as defined by Newstead) 

 v/as found only in the Nigerian, Gold Coast, Gambian, Senegambian and 



* Bull. Bnt. Res. II, pt. 1, p. 33. 



