CELASTRINA ARGIOLUS. 449 



within the very young larvae, the grub eating its way out when the 

 larva is only half grown, proceeding to spin a cylindrical cocoon of 

 yellow silk, from which in a few days the imago emerges. (4) A 

 species of Anomalon (? Angitia pseudaiyjioli), which appears to sting 

 the larva only in the final stages. In this case the Anomalon larva 

 feeds inside the attacked caterpillar, which pupates in due course, the 

 hymenopterous parasite emerging from the pupa which it has, of course, 

 destroyed. As bearing on Weismann's suggestion noted above, 

 Edwards observes that, on June 20th, 1878, he saw in the woods a 

 mature larva of C. pseudargiolus, and, on its back, facing the tail, a 

 large ant. At less than two inches behind, on the stem, was an 

 example of the Anomalon just noted, watching its chance to thrust its 

 ovipositor into the larva. He continues : "I bent the stem, and held 

 it horizontally before me without alarming either of the parties ; the 

 hymenopteron crawled a little nearer and rested, and again nearer, the 

 ant standing motionless, but plainly alert and knowing of the danger. 

 After several advances, the ichneumon turned its abdomen under and 

 forward, thrust out the ovipositor, and strained itself to the utmost to 

 reach its prey ; the point was just about to strike the extreme end of 

 the larva, when the ant made a dash at the ichneumon, which flew 

 away, and, so long as I stood there, at least five minutes, did not 

 return. The larva had been quiet all this time, its head buried in a 

 flower-bud, but the moment the ant rushed, and the ichneumon fled, 

 it seemed to become aware of the danger, and thrashed about the end 

 of its body in great alarm. The ant saved the larva, and it is certain 

 that ichneumons would in no case get an opportunity to sting, so long 

 as such a vigilant guard was about. It seems that the advantage is 

 mutual between the larvae and ants, and that the former know their 

 protectors, and take satisfaction in rewarding them. This was the 

 only occasion which has fallen under my notice in which the actual 

 attempt to sting was defeated, but, on June 16th, 1881, several 

 larvae and several ants were observed on a stem of Cimicifuga racemosa 

 about which an Anomalon was hovering ; it came very near one larva, 

 but an ant, not standing upon the latter, ran at the fly, which then 

 departed. On June 20th, 1879, another Anomalon was observed 

 creeping along a stem on which was a halfgrown larva but no ant ; 

 the ichneumon moved up, put one leg on the larva, rested an instant, 

 turned round, and, when apparently about to give the fatal thrust, 

 hesitated, and, after standing quiet more than two minutes, flew away; 

 the conclusion was reached that either the larva was too young for the 

 purpose of the ichneumon, or the latter discovered that it had already 

 been parasitised" (Butts. North America, ii., Lye. pp. 14-15.) 



Pupation. — When fullfed the larvae change to a dull livid pink 

 colour, this change being effected in the course of a few hours, when 

 they show a disposition to descend the sprays of ivy, and it was found 

 that a few ivy leaves, scattered over the bottom of the cage afforded 

 them suitable conditions for pupation. The larva spins a small mat 

 of silk in the concave side of an inverted ivy-leaf, a pretty strong 

 silken girdle is made, which fits into the hollow between the pupal 

 thorax and abdomen ; this, with the anal support, secures it firmly, its 

 face to the leaf ; the pupa itself, of a rounded dumpy shape, reminds 

 one somewhat of that of Rumicia phlaeas, and is of an ochreous tint 

 dashed and blotched with brown. The pupal stage of one of these lasted 



