50 



THE CLASS OF INSECTS. 



pseudova, must depend upon a something impressed upon t/ie 

 constitution of the parent before it was brought forth by its 

 viviparous progenetrix." (Huxley.) 



Siebold has also shown that the "ova of the Queen-beie pro- 

 duces females or males, according as the}- are fecundated or 

 not. The fecundated ovum produces a queen or a neuter 

 according to the food of the larva and the other conditions to 

 which it is subjected ; the unfecundated ovum produces a 

 drone." This is analogous to the agamic reproduction of 

 Aphis, and " demonstrates still more clearl}- the impossi- 

 bility of drawing anj' absolute line of demarcation histologi- 

 cally between ova and buds." 



This process of reproduction is not known in the Mj-riapods. 

 It occurs among the mites (Acarina), and occurs in isolated 

 genera of Hemiptera {ApMs^ Chermes, Lecanium, and Aspidi- 

 otus according to Gerstaecker). 



Among Lepidoptera the Silk-moth sometimes la3's fertile 

 eggs without previous sexual union. This verj^ rarely hap- 

 pens, for M. Jourdain found that, out of about 58,000 eggs 

 laid by unimpregnated silk-moths, nianj^ passed thi'ough their 

 early embryonic stages, showing that they were capable of 

 self-development, but only twenty-nine out of the whole 

 number produced caterpillars. (Darwin.) Several other moths * 

 have been found to la}^ fertile eggs without previous sexual 

 union, and among Hj-menoptera, N'ematus ventrkosus, Cynijis, 

 jSfeuwterns, perhaps Apophyllus (according to Gerstaecker), 

 and Cynips spongifica (according to Walsh, Proceedings of 



* We give a list from Gerstaecker (Bronn's Classen mid Ordniingen cles Thier- 

 reichs) of all the kuo^\^^ cases of agamic reproduction in this suborder, M"ith the 

 number of times the phenomenon has been observed, and the names of the ob- 

 servers. 



Sphinx Kgustri, once (Treviraniis). 

 Smerinthus pojntU, four times (Xord- 



mann). 

 Smerinthus ocellatus, once (Jolmston). 

 Euprepia caja, Ave times (Brown, etc.). 



" vilHaa, once (Stowell). 

 Telea Polyphemus, twice (Curtis). 

 Gastrojmcha pini, three times (Scopoli, 



etc). 

 Gastropacha quercifoUa, once (Basler). 

 " potatoria', once (Burmeis- 



ter). 



Gastropacha quercus, once (Plieninger). 



Liparis dispar, once (Carlier). 



" Eager moth" {7 Liparis dispar), (Tardy, 



Westwood). 

 LijKiris ochropoda, once (Popoft"). 

 Orgijia pudihunda, once (Werneburg). 

 Psyche apiformis, once (liossi). 



" heii.v (Siebold). 

 Solenohia lichenella (Siebold). 



" triquetrella (Siebold). 

 Bombyx mori, several times. 



The subject has been also discussed by Siebold in his work entitled, A true Pai'- 

 thenogetesis in Lepidoptera and Bees; by Owen, m his "Parthenogenesis," and 

 by Sir J. Lubbock in the Philosophical Transactions, London, vol. 147, pt. 1. 



