LIST OF LEP1D0PTEKA. 83 



criminately upon the various species of willow, sallow, and poplar, which grow 

 in this country. M. Duponchel gives lime as one of its food-plants, but I 

 never saw or heard of its being found upon that tree. Accident has hitherto 

 prevented my rearing the larvae which I have found in July, so that I am 

 unable to prove its double-broodedness from my own personal experience, but 

 upon taking up "L'histoire Naturelle des Chenilles," by M. Duponchel and 

 Guenee, a few days since, I found my suspicion most satisfactorily confirmed 

 in the following words: — "This larva feeds upon willow, poplar, and sometimes 

 also lime. There are two broods. The first brood appears in June, and pro- 

 duces the perfect insect at the end of a month or six weeks. The second 

 appears in October, and does not complete its transformation till the end of 

 April or the beginning of May in the following year." — "Cette chenille vit 

 sur le saule, le peuplier et quelque fois aussi sur le tilleul. Elle a deux gener- 

 ations. Les individus de la premiere se trouvent en Juin, et donnent leurs 

 papillons au bout d' un mois ou six semaines. Ceux de la seconde paraissent 

 en Octobre, et ne deviennent insectes parfaits qu a la fin d' Avril, ou au com- 

 mencement de Mai de V annee suivante." The egg, which is white and opaque, 

 and more raised than those of the Notodontce, is laid on the under side of 

 the leaf. I have not unfrequently reared the young larvae from eggs thus 

 found. I am happy to find that my indefatigable correspondent, Mr. Gascoyne, 

 of Newark, who has so satisfactorily supplied the "only link wanting in my 

 chain of evidence" in support of the double-broodedness of N. dictcea and N. 

 ziczac, has got a goodly stock of the pupae of P. palpina, and fully intends 

 to corroborate M. Guenee's remarks next season. (C.) 



57. N. dictcea. — With this insect we enter upon a wide field of discussion, 

 the double or not double-broodedness of some of the Notodontidce. My own 

 opinion is, that in a state of nature they are not so. That I have never 

 succeeded in rearing two broods in the same year, I readily admit, proves 

 nothing, because others may, nay, have done so. But still I am disposed to 

 think this an abnormal circumstance. I ground my opinion on this fact. For 

 years I have been in the habit of digging up the pupae of Dictcea and Camelina. 

 During that period I must have had at least two hundred of the former, and 

 five hundred of the latter. Now the supporters of the double-brooded theory 

 maintain that eggs are hatched in June, or thereabouts, and that the larvae 

 feed up and produce perfect insects in August and September. If this be 

 correct, is it not singular that not one of the pupae dug up in August and 

 September, should ever appear in the perfect state till the beginning of the 

 following summer? And yet this has been unquestionably the case with me; 

 I have even tried to force pupae obtained in August, but in vain. They have 

 indeed appeared somewhat earlier in the ensuing year, but never the same 

 year. A gentleman, signing himself F. K., "Intelligencer," vol. ii., page 172, 

 says he found a full-grown larva of Dictcea some time in July, which immediately 

 spun up, and produced a perfect insect in about three or four weeks. Was 

 the pupa left in the open air, as in a state of nature? If not it in no way 

 affects my argument. Again, at page 173, Mr. Naish states that "last spring 

 I had two female Dictcea, which laid a fine lot of eggs; these appeared in 

 the imago state the beginning of this month," that is, August. Now last 



