﻿294 LÉPIDOPTÉROLOGIE COMPARÉE 



graminatic outline. Figs. 15 and 16 are not m alignment, but 

 the distance between them (^measured on the photographs) is 

 about 12 mm., a portion of the dorsal head pièce appearing m 

 Fig. 16. There are very small lenticles over the same areas as 

 the spiCLilar hairs, perhaps more numerous near the spiracles, 

 most numerous on the prothorax (Fig. 16). There are several 

 on the anterior legs at an articulation and one is seen on one 

 of the second pair of legs. There are a few cremastral hairs, 

 very short (about 0.07 mm.) and with ends that obviously 

 represent the anchor-like end often seen in cremastral hairs; 

 they are small knobs transversely widened and overhanging 

 towards the base, there is often a bend just below it They 

 must be functionless and are only vestigial. On the dorsum of 

 the seventh abdominal segment, is the conspicuous scar of the 

 honey gland, a transverse mark wider at the ends, where the 

 tissue is so thin as to look like two apertures. 



The Life History of Lycaena alcon proves therefore to be 

 quite paralleJ to that of L. arion but amongst the points of 

 différence there is one that is of a remarkable character. Both 

 leave tlieir plants and are accepted by the ants as very small 

 larvae, but in the case of L. arion this small larva is in the 

 fourth instar, remarkably small for that stage but with a panoply 

 of skin hairs and tubercles very closely packed and suitable for 

 a much larger larva. It undergoes no further moult. 



L. alcon leaves the food-plant in the third instar, and instead 

 of being like the larva of L. arion spécial ly equipped with hairs, 

 etc., that would be suitable when it becomes a larger larva, it 

 is to ail appearances an ordinary third stage Lycaenid larva, 

 exactly parallel to those of the Plebeiid and other Blues that 

 go into hybernation in the third instar. Like L. arion however, 

 it undergoes no further moult, and présents the remarkable and 

 I believe unique character of a Lycaenid larva that has only two 

 moults (three instars). 



One corollary of this is that when full-grown, the larva, not 

 being provided with a spécial arrangement of hairs, etc., in view 



