6 ROBERTS, On two cases of Parallelism in the Aphidce. 



therefore has proposed the name of tullgreni for Tull- 

 gren's species. Mine seems to correspond closely with 

 tullgreni, although there are certain small differences in 

 the venation of the wings. As I find, however, that there 

 is considerable variation in the venation of individuals of 

 even the same colony, I think these discrepancies are 

 slight enough to be disregarded. 



The insect is of interest for several reasons, not least 

 of which is the curious resemblance the wintering form 



Text-fig. I. — Hamafnelistes tullgreni. 

 Sexupara. 



bears to a coccid. Tullgren calls this the " aleurodiform " 

 generation, and it is a very apt name. It has been found 

 on birch (Betula spp.), but this appears to be the second- 

 ary host and the primary host at present remains to be 

 discovered. 



Early in May last I sent one or two twigs of birch 

 with a certain species of aphid to Professor Theobald. In 

 his reply he told me that on one of the birch twigs I had 

 accidentally sent also a black scale-like aphid (evidently 

 the mature winter-form of this species). I was, how- 



