1660 Insects. 



clown into the earth, as the last one I had did; but on looking the next day, I found 

 it gnawing the wood near the top of the box, and endeavouring to make a case. It 

 was immediately removed into a flower-pot, containing earth, and supplied with leaves, 

 pieces of bark, and some fragments of decayed wood ; it chose the latter, probably on 

 account of its softness, and formed a case on one of the pieces, covered with chippings, 

 similar to those of Cerura vinula, but looser in texture. I observed, while forming its 

 case, that when any of its spines interfered at all with the freedom of its movements, 

 it immediately bit them off". On September 18th I was much surprised to find a 

 splendid female moth had emerged from the pupa, which had the abdomen thin and 

 small, apparently quite destitute of eggs. — John R. Hawley ; Hall Gate, Doncaster, 

 October 19th, 1846. 



Causes of occasional scarcity among Lepidoptera. — The passing remarkable season 

 has brought forcibly before our notice two circumstances respecting Lepidoptera which 

 had not previously, that I am aware, attracted much attention, but which will, in a 

 great measure, I think, account for their occasional abundance or scarcity ; these are, 

 the appearance out of season of the perfect insect, and the number of barren females. 

 When moths which should come out in June make their appearance after the middle 

 of September, — as in my Alni, for instance, — it is obvious that, even in the case of 

 fertile eggs being deposited, the young larvae must perish for want of food. But pro- 

 bably a more frequent cause of scarcity is a want of fertility in the female, which may 

 have its origin in atmospheric influences, or be the result of some accidental quality 

 in the food of the larva. Perhaps the same cause that has produced extensive disease 

 in the vegetable kingdom may have equally influenced the insect world : be that as it 

 may, I think it behoves every naturalist to make and record careful observations in his 

 own peculiar department, with a view T to the elucidation of these phenomena, and the 

 discovery, most probably, of some new and interesting feature in the economy of cre- 

 ation. From whatever cause, the number of mistimed appearances and barren females 

 has this year been unusually great. In spring I bred a number of Orthosia munda 

 they were very fine, but marked by two peculiarities, — the absence of the black spots 

 in the wing in every individual, and in the females, the thin shrunk-up abdomen en- 

 tirely destitute of eggs. I was anxious to perpetuate the breed, that I might try the 

 result of a variety of food with the larva?, but the females seemed to possess no attrac- 

 tions whatever for the males, and I of course failed. In this case I thought the food 

 might have been the cause, as they were fed entirely on poplar. Last year, the female 

 Mamestra suasa that were taken here, were all of the thin-bodied kind, and not an 

 egg was obtained from them. This year the females were all plump, and invariably 

 deposited their eggs soon after being caught, while, on the other hand, every female 

 Orthosia populeti, O. miniosa, Glaea rubricosa, Apamea congener, Xylophasia scolo- 

 pacina, and Acronycta ligustri, that I have taken, have had the thin barren appear- 

 ance, and been evidently quite destitute of eggs. It would be curious to ascertain 

 whether this peculiarity is invariably the effect of external causes, or whether some 

 genera and species are more liable to it than others ; and such can only be done by 

 careful observation. Can it be that there is among moths, as among bees, &c, a third 

 sex ? If so, as among bees, the perfect development of the female is known to be the 

 result of peculiar food ; so we may, perhaps, in this cause find a solution for the mys- 

 tery in question, and eventually be able to insure the perpetuation of rare broods by 

 attention to the food of the larva?.— Id. 



