ACADEMY OF SCIENCES. 61 



young larva to find its proper food, when, after its winter sleep, the plant 

 should put forth its spring adornment. The Amorpha is particularly local, and 

 not easy of cultivation, so I had no means of following up my observations, 

 but by travelling some miles to the spots in which the plant happens to grow, 

 and these being at a distance of from 30 to 100 miles from San Francisco, the 

 opportunities afforded me were but few. Every season, however, I followed 

 up the small trail which I had struck, and this year, I was fortunate enough to 

 have my hopes of the discovery of the earlier stages of this charming species 

 crowned with complete success, and at White Sulphur Springs, Napa Co., on 

 the 7th of May last, I had the extreme gratification of seeing the caterpillar 

 for the first time. Upon some plants of Amorpha, which very specimens I 

 had carefully searched for five years, I found 19 examples in different stages 

 of growth; and have since had the satisfaction of seeing all transform to 

 the chrysalis state; and some few reach the imago. The species appears to be 

 as delicate in physical habit as its colors are beautiful, and it feeds exclusively 

 upon the plant on which it was originally found. I tried the caterpillars with 

 Psoralen, Astragalus and Hosachia, among Californian plants, and with Cassia 

 and Sivainsonia among exotics, but it would eat none of them, and no matter 

 how dry the leaves of its own food might be, it devoured them readily, and 

 appeared to thrive. The result of my first experiment with this species has 

 been as follows: 



The full grown larva? began to change to the chrysalis on the 9th of May, 

 and by the 14th, all had gone into that stage; the first imago emerging on the 

 28th. I should add that in addition to the 19 nearly full grown larva which I 

 brought successfully to the chrysalis state, I found four younger ones, two of 

 which had scarcely passed the second moult, the other two being a little older. 

 The whole of these, however, died soon after my reaching home. I have 

 raised out of my 19 caterpillars, seven males and four females, seven of the 

 remainder dying in the chrysalis stage from some singular disease. Without 

 any mark to proclaim any kind of sickness, about the third or fourth day 

 after the transformation, a livid spot appeared upon the basaof the abdominal 

 region, and in two days more this was extended to the whole surface. By the 

 end of the 10th day, the chrysalis had assumed a blackish hue, and withered 

 completely away, leaving only the dry husk to tell the tale. No parasite has 

 emerged from these specimens, nor does it appear likely that any such event 

 may happen, as the remaining specimen was infested by a large Dipterous 

 insect, common to many species of Lepidoptera which has already produced 

 its imago. I regret that a knowledge of the egg has so far escaped me, but I 

 hope to be able to furnish this fact before the close of the year. Mr. E. H. 

 Stretch was kind enough to make a figure of the larva and chrysalis, which 

 will be published in Mr. W. H. Edwards exquisite work on the Butterflies of 

 North America. In the meantime I offer the following description: 



Larva. General color pale yellowish green. Head rather small, bluish 

 green, with a few short hairs in front. Body entirely covered with minute 

 black irrorations, with a faint indication of a pale dorsal stripe. There is a 

 very distinct white lateral stripe, enclosing the spiracles, which are bluish 

 white and are surrounded by a yellow dash. Above the spiracles are ten well- 



