LIST OF LEPIDOPTERA. 85 



appearance of a single red tubercle. The larva feeds on various species of 

 poplar, and sometimes, though rarely, upon sallow. Various entomological 

 authors mention birch as one of its food-plants, but I am convinced wrongly. 

 I have been in the habit for some years past, of taking both egg and larva 

 on a moor in Derbyshire, where both aspen and birch grow freely intermixed; 

 but though I have beaten and examined each carefully and repeatedly, I never 

 found a single Dictcea upon birch, nor have I ever heard a single authenticated 

 instance of its being found upon that tree. 



Mr. Stainton, in the "Manual," mentions September as the only month in 

 which the larva is to be found; I can only say that I have several times 

 found it full-fed as early as July, and as late as November. I have also 

 had the larva full-fed in July, from eggs found in June, and in both these 

 instances the perfect insect appeared in August. I thence come to the 

 conclusion that the insect is most undoubtedly double-brooded, and it is a 

 perfect marvel to me how any experienced entomologist can for one moment 

 doubt the fact. Mr. E. Shepherd, "Zoologist," vol. xiv., page 5293, says in 

 reply to Mr. Naish, that in order to complete the chain of evidence in favour 

 of the double-broodedness of Dictcea, it must be proved that the May moths 

 are the parents of those found in August. Now if I find a full-fed larva 

 in July, common sense tells me that the egg which produced it must have 

 been laid in May or at the beginning of June. My larva spins up, and the 

 perfect insect appears in August. Therefore the moth which laid the egg in 

 May, is the parent of the one which appeared in August. Mr. Gascoyne 

 tells us, "Zoologist," vol. xv., page 5826, that at the end of July, 1857, he 

 took a full-fed larva of Dictcea; it spun up and produced a female moth at 

 the end of August. He put it out of doors, and a male was immediately 

 attracted, and on the 29th. of August, she was busily depositing her eggs. 

 The chain of evidence is therefore complete, and according even to Mr. E. 

 Shepherd, N. dictcea is double-brooded. 



In September, 1857, my friend Mr. Bree, had full-fed larvae and pupa? 

 of Dictcea, reared from eggs laid by a moth bred from eggs laid by another 

 moth in May. Both these insects were bred by Mr. Naish. As this, how- 

 ever, took place in confinement, I shall, I suppose, be told that it is no 

 argument in favour of my theory, as the larva? being deprived of their usual 

 quantum of air and exercise, were obliged to take to premature development 

 by way of amusement. When you find a larva full-fed in July, and it 

 immediately spins up, it cannot in the least signify whether the pupa be kept 

 in-doors or out, for the difference of temperature is so slight, that it cannot 

 make more than a few days difference in the appearance of the perfect insect. 

 I have also no hesitation whatever in saying, that as far as my own experience 

 goes, confinement does not make any material difference when the larva? are 

 reared from the egg. Were this the case, Mr. Stevens and myself would 

 have bred some autumnal specimens of N. carmelita and 2V. cucullina, in 1854; 

 we had then each a brood of eggs in May, and our larva? were full-fed and 

 spun up long before the usual time; my Ciicullince were all spun up the 

 first week in July, and in the wild state the larva is generally not full- 

 fed till September, yet not a single moth appeared till about the usual time 



