LYCAENA AEION. 333 



devour and too heavy to remove from the nest, or the larva itself may 

 make the cell as a protection ; the presence or absence of silk in the 

 formation of the cell would serve to decide this question. In either 

 case such pupa? as are discovered by the ants immediately after their 

 change, while still soft, would very probably be devoured by them, 

 (the larva, even when preparing for the change, being no doubt too 

 familiar an object to be frequently attacked), and this fact may 

 perhaps account for the destruction of a number of pupa?. It does not 

 of course follow that the larvae are necessarily carnivorous because they 

 live in ants' nests, but it seems to me that it is the only theory 

 hitherto advanced which fits the facts so far as they are yet known ; 

 further facts may of course come to light which will prove this to be 

 a mistaken hypothesis, but that ants' nests, and particularly those of 

 F. ffava, are the normal place of abode of the larva? of avion during 

 the whole of their final instar appears to me to be almost beyond 

 dispute. — G. Wheeler.] 



The larva when newly hatched is almost colourless, and if it may 

 be said of the egg that it is difficult to see, the larva when at rest may 

 certainly be described as almost invisible, so closely does it assimilate 

 in coloration to the white base of the thyme blossom on which it feeds. 

 As it grows, however, it becomes more conspicuous, and perhaps less 

 retiring in its habits, for, when rearing it in confinement, I have 

 frequently found it crawling or resting exposed on the stem of the 

 flower-head, and sometimes even on a leaf of the growing plant 

 (Ray ward, in litt.). 



The larva in at least its first two instars and usually the third, lives 

 in the interior of the flowers eating the pistil, germen, and often 

 portions of the stamens and corolla. Its method of entry and leaving 

 is by a hole in the calyx, though when older it will attack the flower 

 from above and will even eat portions of leaves (Chapman). 



The honey-gland of the larva of Lyc.ena arion. Symbiosis 



BETW T EEN THE LARVA L. ARION AND FORMICA FLAVA. The Slliall, 



elongated, transverse honey-gland is on the dorsum of the 7th abdominal 

 segment. It is formed of glassy- white pyriform processes varying in 

 size, some extremely minute, those bordering the edges of the gland 

 furnished with excessively small, white bristles, each process bearing 

 four or five ; these are in the form of a fan with diverging points, and 

 all are directed towards the central aperture, the whole forming a 

 fringe surrounding the gland ; obviously for the purpose of holding 

 the bead of liquid in place, and probably also to serve as a protection 

 to this apparently sensitive organ. The gland was first noticed in 

 the larva of this species by Frohawk, who, on August 11th, 1902, 

 placed a living larva of arion with four individuals of Formica fiara, 

 which ran to it, waving their antenna? over and upon it, apparently 

 smelling and licking it, being particularly attracted to the dorsum of 

 the 7th abdominal segment. First one and then another of the ants 

 would run over the larva, and then stop to lick this part of the back ; 

 a big bead of moisture was then observed and one of the ants touched it 

 with its mouth, when the bead instantly disappeared. He then detected 

 on the dorsum of the 7th abdominal segment, the small elongated trans- 

 verse gland which attracted them. Another larva was examined under 

 the microscope whilst feeding ; and it was noticed that during the opera- 

 tion the gland kept throbbing, so the ants w T ere placed close to it, and 



