PARTHENOGENESIS OR AGA3IOGENESIS IN LEPIDOPTERA. 29 



pupa in a closed box, that the latter was opened some time after, 

 and contained a female imago and many young larvae, dead. LASIO- 

 CAMPIDES. Lasiocampa quercm. Tardy (teste Newman) bred three 

 parthenogenetic broods of perfectly vigorous and full-sized moths. 

 Mory of Basle, Soc. Ent., April 1st, 1895, also records many 

 larvae from unfertilised eggs. L. trifolii is recorded by Bouskell, 

 Trans. Leices. Lit. Soc., iv., p. 422, as laying a few unfertilised eggs in 

 1896, which hatched in the following spring, and shortly afterwards 

 died. Eutricha (Gastropacha) quercifolia. Baster (teste Bernoulli) ob- 

 tained fertile eggs from an isolated bred female, Cosmotriche (Odonestis) 

 potatoria and Dendrolimus pint, are both mentioned by Newman in his 

 Essay Phys. Charac. BOMBYCIDES. Bomby.v mori. Many cases have 

 already been dealt with at length. SATURNIIDES. Saturnia pavonia. 

 Noticed by Newman, Essay Phys. Charac. ; also by Bouskell, Trans. 

 Leic. Lit. Soc., iv., p. 422, who mentions that a female laid six eggs in 

 her cocoon, she being unable to get out ; these all hatched. S. pyri is 

 mentioned by Newman, Essay Phys. Charac. TeJea polyphemus. 

 Curtis (teste Filippi) obtained fertile eggs from a moth that emerged 

 from a single cocoon in his possession, and that had come from 

 America. SPHINGIDES. Smerinthus ocellatm. Newman, Essay. Phys. 

 Charac. Class. ; Brown, Entow.., v., p. 395 ; Headly, Trans. Leices. 

 Lit. Soc., iv., p. 421, the latter mentions that of the eggs laid, 75 per 

 cent, hatched. S. populi. Kipp (teste Siebold) reared both sexes from 

 unfecundated eggs ; Newman, Essay Phys. Charac. Class. ; Bouskell, 

 Trans. Leices. Lit. Soc., iv., p. 421, mentions twenty out of seventy 

 eggs hatching. S. tiliae. Brown, Ent., v., p. 395, no data. 

 Acherontia atropus. Geddes and Thompson, Evolution of Sex, no data 

 given. Sphin.f lit/ustri. Newman, Essay Phys. Charac. in Classif. ; 

 Nix, Entom., iv., p. 323, all eggs hatched in this brood. Clogg, 

 Entom., v., pp. 356-7, fifty eggs hatched out of the brood. GEOMETRIDES. 

 Phigalia pedaria. Newman, Entom., ii., p. 28, records the laying of 

 many eggs by three unfertilised females at end of February, 1864, and 

 states that, on April 17th, the cage was swarming with newly-hatched 

 larvae. He failed, however, to get imagines. 



Although it may safely be assumed that parthenogenesis does occur 

 in Lepidoptera, yet, as we have just said, it must be confessed that 

 the material based on true scientific experiment is not large, and that 

 many careful observations based on the most exact experiments are 

 required. The elucidation of the peculiar phenomena presented, is 

 worth all the patience with which the entomologist must attack this 

 subject, and he would have the reward of knowing that he had helped 

 to make clearer one of the greatest mysteries of insect life. 



The phenomenon of parthenogenesis appears to me to be explicable 

 only by supposing that the potency of the male element is handed 

 down generation after generation, and that former fertilisations affect 

 the embryo, independently of the actual union which fertilises the 

 ovum. The male element must be looked upon as possessing, not 

 only a great and direct influence on the development of the eggs im- 

 mediately fertilised by it, but also on the eggs of successive issues not 

 directly fecundated. That this is probably so, is shown by the fact 

 that the unfertilised egg often undergoes varying conditions of deve- 

 lopment, short of the actual development of a perfect embryo. This 

 was foreshadowed in our notes on " the ovum," where the variation 



