118 
MEMOIRS OF THE QUEENSLAND MUSEUM. 
Zoyphium) ; second cubital cell of the usual triangular form, but with a face on 
marginal, nearly as long as lower side beyond second recurrent nervure ; first recurrent 
ending a considerable distance from end of first cubital ; marginal cell pointed, but 
not quite on costa, and not distinctly appendiculate ; knees, tibiae (hind pair with a 
dusky suffusion behind) and tarsi red ; abdomen polished, with thin silvery white 
hair at sides ; apical plate narrow. 
Bribie Island, Queensland, Nov., 1918 (H. Hacker). Buns in the table near 
Z. argyreum Hacker & CklL, or possibly Z. iridipeiine Turner, but very distinct from 
both. Z. argyrevm has a j)ale clypeus. 
Turner reinarked (1914) that Zoyphium could oidy be separated from 
Sericophorus by the absence of an appendix to the marginal cell. He questioned 
whether the genera should be kept apart. In Sphodrotes the marginal cell is obliquely 
truncate, with the apex far from costa, and appendiculate. In Sericophorus this 
truncation is smaller, the tip more nearly approaching the costa. The truncation is 
very narrow indeed in S. bicolor Sm., yet it is there, and a long appendicular nervure 
is present. In Zoyphium the tip has moved a Imost to the costa, and the appendicular 
nervure has disappeared, or is represented by the merest stump. Thus the character, 
though rather insignificant, does serve tcj distinguish the genera without fail. It is 
possible that microscopic studies of the mouthq)arts and genitalia will eventuallv 
indicate that there has been parallel evolution, some, species of Sericophoriis and 
Zoyphium being more nearl^\- related to one another than to their ostensible congeners. 
If we take oidy the type species of the two genera, the differences apjiear more 
numerous. Thus, in Herkophorus [S. rhalybcrus Sm.) theanallobe of hind wing is larger ; 
in Zoyphium (Z. sericeum Kohl) it is small. In S'., the basal nervure falls short of the 
nervulus ; in Z. it goes beyond (basad of) it. In N. the second cubital cell receives the 
recurrent nervure far beyond t he' middle ; in Z., at the middle. In S. the third discoidal 
hardly bulges outward apically ; in Z. it distinctly bulges. Unfortunately these 
characters are not constant within the genera. Thus in Nericophorus bicolor Sm. the 
basal nervure goes basad of the nervulus, while in 8 . viridis Sauss. it falls a little 
short of it. In Zoyphium crasskorne Ckll. the basal nervure goes far basad of the 
nervulus, and the second cubital cell receives the second recurrcjit nervure far beyond 
the middle. In Z. affine H. & C., the basal nervure goes a moderate distance basad of 
nervidus, and the second cubital receives the recurrent only slightly beyond the 
middle, thus approaching much more nearly the venation of the genotype. In Z. 
■spJendidum H. &. C„ the second recurrent is far beyond middle of second cubital, in 
this respect resembling Sericophoriis. 
It remains to be learned whether the habits of the two genera differ api>reciably. 
It is a strilcing example of the influence of convention or custom that genera so 
nearly allied as Serkophorus and Zoyphium are separated, Avhilc the characteristic 
Australian Acanthoskthus, with many species, is treated as a subgenus of Nysson. 
I suggest that Acanthoskthus should be projuoted to generic rank. 
