SCIENTIFIC NOTES. 77 



swim, and doos not travel backwards. Now I think Professor Dyar's 

 explanation of the coloration assumed by the larva of S. libatrix before 

 pupation is most obvious, simple, and generally admirable. Firstly, 

 because S. libatrix spins quite a close cocoon in which the larva is 

 invisible (it may have acquired less exclusive habits in America). 

 Secondly, it does so by drawing together green leaves in which black 

 coloration would make it more conspicuous, and thirdly, tlie black 

 marking is very restricted and does not affect the anterior extremity of 

 the larva. 



The blackening does not ensue at once, but only after the cocoon 

 has been completed, it has a very restricted area, related obviously to 

 the imaginal wings, and is probably related to the impending change 

 to a black pupa. I incline to think it is an inevitable resuft of this 

 pupal coloration in some way, probably in that I have suggested, and 

 if it has in itself any useful function it cannot be that advanced by 

 Dr. Dyar. It is of quite a different character from that which is so 

 common in green tree-feeders that bury in the ground and often have 

 an intermediate period of wandering on the ground, as is the case in 

 most_ of our Sphingids, some Notodonts, &c., useful protectively, but 

 physiologically no doubt associated with the loosening of the larval 

 epidermis and the growth of the cells to form the pupal covering— a 

 separation of the larval epidermis, a beginning of its definite decay and 

 change of colour as a result. A separation of the immediately under- 

 lying coloured tissues, and other changes may be elements in the 

 result, but a definite development of pigment is not one of them, as it 

 is in -S'. libatnx.~T. A. Chapman, M.D., F.Z.S., F.E.S., Betula, Reigate. 



Hybernating stage of Pyeameis cardui. — An interesting item 

 concerning Pyrameis cardui is recorded by Eaton in the E.M.M., 

 p. 42, where he notes that "near the mouth of the river Axe, on 

 December 30th, in the afternoon, he saw a much worn P. cardui dis- 

 porting itself along the sunny side of a wall, and three others on the 

 cliffs at Seaton on January 2nd." The Editors consider this an " un- 

 precedented record," and, further, that "they can scarcely have been 

 other than individuals aroused from hibernation by the prevailing 

 warm weather," also that " they teach us how little we know about the 

 hibernating habits of the insect in this country." They add : "We cannot 

 call to mind anything on the subject save Mr. J. H. Carpenter's note 

 E.M.M., vii. (2nd ser.), p. 279." There appears to be no evidence 

 except Mr. Carpenter's record of having seen a female example, three 

 or four years previously on the Sunday preceding Christmas-day, in 

 cold weather, between the two overlapping pales of an oak fence in the 

 Valley Road, Streatham, which, although sluggish at the time, quickly 

 revived, and died a few days afterwards— thVt the insect hibernates 

 in the true sense in this or any other country, and it Avould appear 

 that the P. cardui observed by Mr. Eaton were doing what the winter 

 survivors do normally during December-February in southern Europe. 

 There has been, I believe, no frost yet this winter (189H-9) in Devonshire 

 (in London there have not been more than half-a-dozen frosts, and these 

 not more severe than one can often experience in the Alps at 5,000ft. 

 in mid-August nftor a brilliant day). Whilst agreeing that we know 

 but little about the hibernating habits of the insect in this country, we 

 would further suggest that the following notes have something " to do 

 with the subject "—/;?if. Ikcurd, vii., pp. 110-111 ; viii., pp. 203-201 ; 



