THE MYSTERY OF LYC.ENA AFJON. 245 



The Mystery of Lycaena arion. 



By T. A. CHAPMAN, M.D. 



The mystery of Lycaena rt)tr)?t remains a mystery. I obtained eggs 

 at Gavarnie this summer and reared some larvae, of which I succeeded 

 in getting about a score to the last instar (supposed hibernating stage). 

 Though in their fourth and last instar they are only about as large as 

 the larvfe of Af/riades cor'ulun or other ordinary blues when they go 

 into hibernation. They no doubt do something, and without further 

 moult appear (to very few people) the following June quite full grown. 

 The mystery is, what do they do in the interval, where do they live, 

 and Avhat do they feed on ? I hoped to get nearer this by aid of my 

 score or so of caterpillars, but they behaved as they always had done 

 with me previously, after not very many days they were all dead. 

 Though 1 made no further discovery, by watching them more closely 

 and considering them more seriously, I am able to advance a little 

 nearer the enemies' trenches, but so far without the slightest conlidence 

 of beino: able to take them. 



I ottered my larvas the companionship of the proper ant. Without 

 showing enmity, neither ants nor larvjB fraternised in any way. I 

 offered the larvte various kinds of food, all the hopeful sorts of plants 

 I could obtain, of these they seemed to sip the sap of kidney beans, 

 but these they did not eat, nor did they increase in bulk ; other things 

 they would not look at. I had no young green peas available (the date 

 late August), the food that Mr. Frohawk found they would deal with. 

 I offered them mashed ant larviie, which did not even rouse their 

 curiosity. I gave them various hibernating facilities such as have 

 suited other Lycfenid larvse, but they would not settle down until they 

 were exhausted and, in fact, dying. 



These are all facts that have been known for some years to Mr. 

 Frohawk, The Hon. N. C. Rothschild, and myself, and are, one may 

 say, now known to everybody. There are, however, several other 

 points that, in a sense, are equally well-known, and yet, so far at least 

 as I am concerned, were not, for really practical purposes, known so as 

 to be properly appreciated and weighed. 



The central fact of these is that, when the larva enters on this 

 last instar, when it has taken its last moult, and sets out at once on 

 its wanderings, it does not first eat any more of the flower-heads of 

 the thyme. It starts its wanderings, therefore, without any of the 

 stored nutriment that larvae have when they go into hibernation. It 

 wanders about and the real object of these journeys is no doubt to find 

 food. As in captivity it always dies before many days, unquestionably 

 of starvation, it follows that at large it succeeds in finding food Avithin 

 a similar limited period. This does not m the slightest answer the 

 questions, where and what, but it implies that it ought not to be so 

 difficult to somehow follow the larva at large for a few days and see 

 what it does. The structure and small size of the head imply that the 

 food is vegetable and not difficult of mastication. This does not 

 negative the idea that it becomes the guest of ants, but the neutrality 

 ■observed between the larvte and the ants is strongly against it, the 

 importance to the larvfe of an early supply of food would necessitate a 

 prompt treaty between the ants and their guests, if this is how its 

 wants are supplied. 



