112 ARE THE NOTODONTID.E DOUBLE-BROODED. 



in the same year, which circumstance, if true, strongly militates, as it 

 appears to me, against the theory of the insects being double-brooded. 

 Ihe objection applies with greater force to Camelina than to Dictcea, for 

 I have frequently turned up the former the first week in August, the 

 latter only occasionally; but in neither case has the perfect insect ever 

 appeared before the following spring. 



Mr. Crewe suggests two answers to my objection. The cause of my 

 failing even to force them, he considers to be obvious; "because they were 

 not the produce of eggs laid in May, but at the end of June or in July, 

 and were not intended to appear till the following spring." Now this 

 appears to me to assume the whole point at issue between us. I see no 

 reason whatever why the pupae found at the beginning of August, should 

 not be the produce of eggs laid in May, or at the beginning of June. 

 On the contrary, it seems to me, that they unquestionably are the produce 

 of those eggs, and of none other. I confess I do not understand Mr. 

 Crewe's argument here. His eggs laid in May, produced the perfect 

 insect in August. Very well. Those eggs were, of course, laid by the 

 parent which had passed the winter in the pupa state. The eggs were laid, 

 and the parent dies. What then lays those eggs in June and July, the 

 produce of which is not intended to appear till next year? If my friend 

 Mr. Crewe, can answer this question, it is more than I can. But to state 

 the case a little more particularly. I find a fertile $ Dicttea at the end 

 of May; she lays her eggs, which hatch about the second week in June: 

 by the end of July, or beginning of August, they are full fed, and go 

 down. I dig up half a dozen pupae, and try to force them; but they 

 will not be forced. And why? Because, according to Mr. Crewe, they 

 were not the produce of the eggs laid in May, but of those laid in the 

 end of June and July. I ask again, what laid these latter? Supposing 

 this question satisfactorily answered, I would ask, is it possible that an 

 egg of Dictcea, laid on the first of July, could hatch, feed up, and turn 

 to a pupa, by the first week in August? I pause for a reply. 



As to Mr. Crewe's second answer, namely, M. Duponchel's statement, 

 that the spring brood spin up between two leaves, while the autumnal 

 brood burrow into the earth. I place little or no value upon it, that is, 

 the statement. I appeal with confidence to Mr. Crewe, and to every 

 English entomologist, whether they ever knew such a circumstance to occur, 

 as that of Dictcea spinning up between two leaves! But, granting it to 

 have occurred once or twice, it lies with Mr. Crewe, and Messrs. Naish, 

 Harding, and Gascoyne, to assert that it is the custom for the spring 

 brood to do so, if they would build anything upon M. Duponchel's state- 

 ment. That they will not assert this, I am confident. 



To sum up: — I cannot give my assent to the statement, that either 



