60 SPINOUS CURE ANT- CATEKPILLAB, 



kind of plant food. Dr. Harris speaks of having raised it from 

 caterpillars found feeding upon the elm, but makes no mention oi 

 its eating the currant. Dr. Fitch, in his New York Reports, 

 speaks of them as sometimes eating the leaves of the currant, and 

 on the 15tli of July I received a number of these caterpillars from 

 Mr. B. N. McKinstry, of Judson, Kankakee county, accompanied 

 with the statement that they were doing considerable mischief by 

 stripping the leaves from his currant bushes. This is, I believe, 

 the first record of its feeding upon the currant in this State, and 

 it cannot be regarded, at present, as a noxious insect of a serious 

 character. 



I made a few observations upon the individuals sent to me, of 

 some scientific interest, which I will briefly state. 



The chrysalis state, which is stated by Drs. Harris and Fitch to 

 vary from eleven to sixteen days, lasted, in my speimens, only 

 seven days. The weather was excessively hot, the thermometer 

 indicating, most of the time, 100 degrees, which may, perhaps, 

 account for the rapid development. 



As these caterpillars, after they had suspended themselves for 

 the purpose of transformation, hung directly in front of my study 

 table, I was led to observe more closely than I had .hitherto done, 

 the process by which these creatures divest themselves of their 

 larval covering. It appears to consist of two stages : the first is 

 slow, gradaal and almost imperceptible, occupying some twenty- 

 four hours of time, during which, it may be presumed, there is 

 efiected a gradual separation of the larval from the pupal envelope. 

 During this period the caterpillar hangs with its body curved for- 

 wards and upwards, and appears to be almost motionless ; but upon 

 close observation it is seen to undergo almost continuous though 

 slight changes, consisting of a nodding motion of the head, and an 

 occasional variation in the curvature of the body. The second 

 stage is short and active, usually lasting but a few minutes, the 

 object of which is to throw off the loosened larval skin ; first, by 

 bending the body it bursts open the skin upon the back, and then, 

 by a wriggling motion, works it up towards the point of attach- 

 ment, and lastly detaches and throws it entirely off by a series of 

 violent contortians, apparently at the imminent risk of severing 

 the thread upon which its safety literally depends. 



