1022 THE BUTTERFLIES OF NEW EXGLAXD. 



day or two and meanwhile small, greenish caterpillars appeared :il)()iit tlio 

 room, on the walls and bureau. They pupated on the walls, the mop- 

 board, the pin-cushion, the sides of the bureau. The chrysalids were shaped 

 like an ace of clubs." When they emerged the butterfly was identified. 

 "The next year we found one larva on an aphis covered alder, but have 

 never seen one since." This seems to be the earliest observation of the 

 direct association of the caterpillar with the plant-lice, though Abbot 

 records the caterpillar as "covered with a white, loose down" — actually the 

 flocculent secretions of its victims, which become entangled in its hairs ; 

 and the following extract from the note-books of the late Dr. Asa Fitch, 

 written January 7, 1855, show^s that he had noticed it. 



"I wholly forget the history of these specimens; I find the pupae 

 slightly attached to the sides of a pill box, and the butterflies hatched 

 therefrom ; and in the same box some beech leaves and woolly plant-lice 

 (Schizoneura imbricator Fb.). I conjecture the worm from which the 

 pupae came must have been feeding among these lice — but have no recol- 

 lection of the fact." It was not until 1884 that the suspicions of Messrs. 

 Pergande and Riley were aroused. In the following 3'car these observers 

 proved the fact by direct observation, and Mr. Riley published a brief 

 statement to that effect early in 188G. In the same year, in entire ignorance 

 of what had been done, the whole case was worked out with the greatest care 

 by Miss Emily L. Morton of New York, who saw a butterfly deposit an 

 egg "right in the middle of the aphides," observed the larvae devouring 

 the aphides, raised the caterpillars to maturity upon them and found by 

 experiment that they utterly refused to eat the leases of the trees on 

 which they were found. 



Habits of the caterpillar. On this point we are almost entirely de- 

 pendent on the excellent observations of Miss ^Morton and Mr. Edwards. 

 The young larva eats a hole through the summit of the egg, does not 

 devour more of the shell, but 



pushes its way under the larger aphides . . . and forthwith begins to spin for itself a 

 loose web, not close enough to conceal it from view were the aphides away, Init suffi- 

 cient to keep the aphides from walking over the body, and to protect it wheu the moult 

 is approaching, and the skin sensitive. The web seems to be just about the length of 

 the larval hairs from the body. The aphides may be seen running over it, and often 

 get their legs fast in the meshes, and are very apt to l)e devouvod as a consequence. 



Apparently both the first and second moults are passed beneath this 

 filmy web ; but after the second moult (they undergo but three), says 

 Miss Morton, "I find the larvae crawling naked on the limbseekino- fresh 

 supplies of food" ; which found, "they again spin a web, which they leave 

 after the aphides are consumed." Miss Morton thought that in the last 

 stage they no longerattempted concealment, but moved about very quickly. 

 Some which I obtained, however, remained in the web until ready to change 



