NOTES ON HYMENOPTERA. 67 



which I contributed to the Annual of 1866, it is as follows : — 

 " In 1864 I collected a large number of the larvae of Erio- 

 campa ovata, and, in the spring of the following year, bred 

 as many as fifty flies, but all proved to be females." Of 

 this very common species of saw-fly the male is not known ; 

 the female is very abundant in the neighbourhood of Lowes- 

 toft, where the alder, upon which its larva feeds, grows in 

 almost every hedge, and at the sides of every ditch ; I have 

 taken some hundreds of examples in the hope of finding the 

 male. When collecting the laryae in 1864, I selected those 

 of the largest size, judging they would be soonest full fed, 

 and therefore give me the least trouble in attending upon 

 them ; and no doubt such proved to be the case, but it sub- 

 sequently occurred to me, that by adopting this course, I 

 had possibly collected 'the larvae of females only, the male 

 larvae being, probably, always smaller; this supposed error 

 however I determined to rectify ; therefore, being at Lowes- 

 toft last season also, I availed myself of the opportunity, 

 and collected a large number of larvae of all sizes, preferring 

 those of the smallest size I could find; many of these were 

 not more than the eio^hth of an inch in lencrth. The feedino- 

 of these larvae occupied about three weeks; each one, when 

 it had acquired its full growth, buried itself in mould, con- 

 tained in a large flower-pot. 



In the month of April, in the present year, the flies began 

 to issue forth, and continued to do so up to the end of the 

 month; the total number being 132; all proved to be females, 

 with one solitary exception, and that is a male of a species 

 of Nematus. The mystery, therefoi'e, that has hitherto 

 existed with respect to the male of Eriocampaf is undis- 

 pelled. The solution of this mystery is probably to be 

 sought for in another direction. Be this as it may, we are led 

 to the inquiry as to the possibility of the fertilization of the 



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