( Ixviii ) 



pocket, usually so closed by the cuticle reattaching itself to 

 the tissues below, that the point of entry seemed often to 

 have nothing directly to do with the pocket and egg. The 

 egg appeared to increase a little in size, and more completely 

 fill the pocket. Eye movements of the larva within for some 

 time before' hatching were but slight and at considerable 

 intervals. In Trichiosoma tibiale they had much amplitude 

 and were frequent, just as in the sallow species (v. " Trans. 

 Ent. Soc. Lond." 1914, p. 180). What purpose this regular 

 movement of rotation of the head serves is not obvious, but 

 probably has some respiratory object. 



On the day of her emergence (May 14th) this C. sylvarum 

 laid twenty-four eggs. This seemed to satisfy her wants in 

 the matter. On the 17th she laid five eggs, on the 18th she 

 laid two, and made two pockets, but placed an egg in neither. 

 On the 19th she laid two eggs, was quite strong and lively 

 and inclined to buzz and fly. Thereafter she laid no more 

 eggs, and though she continued to drink for a day or two> 

 she gradually weakened, got lethargic and stupid, and died 

 on May 23rd. 



The two eggs last laid did not hatch, and the two before 

 produced weak larvae that soon died. The dead ? contained 

 a goodly number of eggs, I did not count them but perhaps 

 30 to 50. 



I have now a fair number of larvae feeding, in their second 

 and third instars. According to records, unfertilised eggs of 

 C. sylvarum produce males, so this will probably be the result 

 with these larvae. 



One can hardly avoid coming to the conclusion from these 

 observations, that in this species the newly emerged female 

 hastens to lay a certain number of unfertilised eggs (producing 

 males) and then pairs, the remaining fertilised eggs producing 

 females. Further, that the reserved eggs destined to produce 

 females after fertilisation, cannot be laid unfertilised to pro- 

 duce males. This is in some degree confirmed by the fact 

 that a specimen sleeved by Mr. B. S. Harwood, was sent 

 me after its death and equally with my specimen contained 

 many eggs. 



Further, more or less obvious, observations and experi- 



