ii 4 R. W. CROSSKEY 



chir pertain. On the other hand, the correct application of the names Psaronio- 

 compsa Enderlein and Pliodasina Enderlein, which Stone (1963) also treats in 

 synonymy with Simulium s. str., is at present very doubtful because of inadequate 

 knowledge of the two Neotropical type-species : however, it seems certain that 

 few if any of the many South American species of Simulium s.l. can legitimately be 

 assigned to Simulium in the strict subgeneric sense and I therefore omit the names 

 Psaroniocompsa and Pliodasina from the synonymy of Simulium s. str. until their 

 status becomes clear. 



Davies (1966 : 421) has recently given reasons for not accepting the segregate 

 Boophthora Enderlein (type-species Simulium erythrocephalum (De Geer) = Simu- 

 lium argyreatum of Enderlein, not of Meigen, by misidentification) as a valid sub- 

 genus and has included its type-species in Simulium s. str., and in an earlier paper 

 (Crosskey, 19676) I have also treated Boophthora as synonymous with Simulium 

 s. str. However, it now appears to me after evaluation of the segregates of Simulium 

 s.l. on a world basis, rather than with the narrower purview of the Palaearctic 

 Region alone, that Boophthora should be accepted as a separate subgenus (in accor- 

 dance with the view already expressed by Stone, 1963 : 3). The characters for 

 distinguishing Boophthora and Simulium s. str. lie mainly, as Davies points out, in 

 the male hypopygium (with its remarkable very short styles bearing multiple 

 spinules in Boophthora as compared to the enormously long heavy styles with single 

 apical spinule in Simulium), but other characters also provide distinguishing 

 features for adults and larvae (there is no fully satisfactory character for separating 

 pupae of Boophthora from those of all Simulium s. str. on a subgeneric basis) ; the 

 larval abdomen in Boophthora has a pair of distinct flap-like papillae on the last 

 segment in a lateroventral position, and the upper mesopleural region in front of the 

 pleural membrane (sometimes also the upper part of the membrane itself) is haired. 



In all the many Holarctic species of the subgenus Simulium s. str. the basal 

 section of the radius is bare in both sexes, and Rubzov (1959-1964 : 509) cites the 

 character in his diagnosis (' <$ und $ : Die Ader v x ist nackt in der Basalhalfte '), 

 but in some Oriental species of Simulium s. str. the basal part of the radius is haired 

 in the female even though bare in the male as normal. Such sexual dimorphism is 

 of such very rare occurrence in the Simuliidae that erroneous association of males 

 and females was at first suspected, and there is still doubt about the validity of 

 Edwards' (1934 : 104) statement that males have the radial base bare in species of 

 his Group I, Sub-group A yet the females have it hairy : but Puri's (1932&) record 

 of such dimorphism in S.(S.) grisescens Brunetti was based on a series of reared adults 

 which were almost certainly correctly associated. So while it is nearly always the 

 case that the basal section of the radius is bare in Simulium s. str., exceptions have 

 to be admitted into the subgenus on totality of characters even though the base of 

 the radius is haired and in one sex only. A comparable situation exists in the Neo- 

 tropical subgenus Psilopelmia Enderlein in which some species have the basal section 

 of the radius haired and others bare, and in at least one species of which (Simulium 

 (Psilopelmia) downsi Vargas, Martinez Palacios & Diaz Najera) there is sexual 

 dimorphism in the character. 



