NOTES ON HYMENOPTERA. 113 



on one occasion I was watching several females wandering 

 sluggishly over the alder leaves, when a strange looking indi- 

 vidual was observed amongst them ; its motions were equally 

 sluggish, its difference in coloration alone distinguislied it ; 

 on securing the specimen it proved to be a male insect, well 

 known to me, and described by Stephens by the name of 

 Semichroa Alni, the Tenthredo Alni of Linnasus; all the 

 examples, that I have captured, or seen, have been males ; the 

 question therefore to be answered now is, can the Hemichroa 

 Alni possibly be the male of Eriocampa ovata ? 



The neuration of the wings in Eriocampa is so very 

 different to that of the genus Hemichr^oa as to justify fully 

 their generic separation ; both genera agree in having one 

 marginal and four submarginal cells, but in Eriocampa the 

 two recurrent nervures are received, the first in the second 

 submarginal cell and the second in the third cell, whilst in 

 Hemichroa both the recurrent nervures are received into the 

 second submarginal cell. This great and important dif- 

 ference in the neuration of the wings of these insects, compels 

 me to hesitate in expressing a very decisive opinion of their 

 really constituting one species ; great as is the otherwise 

 general resemblance between them, both have a red thorax, 

 and in their general form, kc. have a close resemblance ; both 

 exhibited the same sluggish manner when observed on the 

 leaves of the alder, and I found no other species of Tenthredo, 

 in the same locality, that could possibly have any affinity with 

 either. 



In order to settle this question, if possible, by direct obser- 

 vation, I collected a large number of larvss ; they soon became 

 full grown and then buried themselves in a pot of earth, from 

 these I hope to obtain the sexes. The difference of neuration 

 is the only apparent obstacle to a complete settlement of the 



1864. I 



