216 



Palpomyia and Serromyia 



The above genera may be separated from other ceratopogonine 

 genera by the following characters : both have the wings bare, a cross 

 vein at about the middle of the last section of first vein, connecting 

 it with the third vein, and all, or at least one pair, of the femora 

 with short thorns on the ventral surface. Be^^da and its subgenera 

 differ from Palpomyia and Serromyia in lacking the cross vein above 

 mentioned; JoliannscuicUa differs in having no thorns on the femora; 

 and Hetcromyia differs in having the fore femora thickened. 

 Serromyia differs from Palpomyia in having the hind femora very 

 much thicker than the other pairs. 



The pupa of Palpomyia longipennis Loew does not present any 

 great structural differences from that figured by Johannsen as Bcc::;ia 

 sctulosa Loew. The pupce of the two species of Joliannscniclla which 

 are in the collection here do not present any structural characters 

 which would in any degree encourage one to accept them as of generic 

 value, as the distinctions between one of these species and its congener 

 are much more decided than between the former and that of Palpomyia 

 longipennis. The presence or absence of the cross vein and such 

 characters as the comparative thickening of fore or hind femora, 

 while of value to systematists for the arrangement of species, are not 

 infallible guides to the relationships of species. In mentioning this 

 I may also draw attention to the fact that the presence or absence 

 of ventral bristles on the last tarsal joint is of very doubtful value 

 as a guide to relationships of the sexes in at least some species of 

 this group. As an instance of this unreliability I may say that if 

 this character were used for their separation the male of longipennis 

 Loew would be relegated to Palpomyia in the restricted sense, while 

 the female would fall into the subgenus Sphccromyas. It is thus 

 evident that the subgenus Sphccromyas is an unreliable concept and 

 must be abandoned. 



The habits of the adults of Palpomyia are not well known; in 

 fact but little attention has been paid to this section of the 

 Ceratopogonincc as compared to that given to the blood-sucking 

 species of the group, Cnlicoides spp. From personal observation I 

 infer that the species of Palpomyia and its allies are mostly flower- 

 frecjuenting in the adult stage, though I have seen a large species 

 of Palpomyia feeding upon a perlid. Whether this was really a 

 genuine case of predacity or whether the perlid had been injured 

 prior to the attack of the Palpomyia I can not say, because when 

 I first saw the insects the Palpomyia was in the act of sucking the 

 juices from the thorax of the perlid, which appeared to be almost 

 dead. This observation was made in Britain. 



