152 AGRICULTUllAL EXPERIMENT STATION. 



DESCRIPTION. 



The perfect insect is a beautiful butterfly witli two and a half to 

 three inches expanse of wing. It may be known by the purplish or 

 reddish brown wings bordered by a yellowish or buff band, within 

 which is a row of violet blue spots. Eggs pale yellow and ribbed. 

 A dozen or more are deposited on the stem near the petiole of a 

 leaf. 



The larva when mature is about one and three-fourths inches 

 long ; black, minutely dotted with white and appearing grayish ; 

 back marked b}' a row of eight bright brick red spots. The body 

 is armed with from four to seven stiff branching spines on each seg- 

 ment except the first, giving the caterpillar a formidable appearance. 

 The larvce are social in their habits feeding in groups on the foliage. 

 Chrysalis dark brown, with large tawny spots around the tubercles 

 on the back. 



LIFE HISTORY. 



The butterflies hybernate iu some sheltered place and are on the 

 wing in the spring before the snow is gone, and lay their eggs for 

 the first brood, which in this region hatches in June, and the larvae 

 are mature late in July or early in August, enter the chrysalis state 

 and the butterfly emerges in ten or twelve days. 



This brood soon laj's eggs, which hatch and the larvjB mature ; 

 enter the pupa state and emerge before fall, producing the hybernat- 

 ing brood, completing the life history. 



REMEDIES. 



We find but few remedies suggested iu the writings of entomolo- 

 gists but see no reason why they might not be destroyed by Paris 

 Green on smaller trees and the branches of larger ones within reach 

 of thejsprajnng pump. The colonies could be hand picked. 



The natural enemies of this insect help to keep it in check. Out of 

 half a dozen chrysalids put away to transform by Mr. Briggs, only 

 two butterflies emerged and from all others there came numerous 

 small ichueumon flies. From one of the chrysalids over one hun- 

 dred and fifty came forth. Some of the specimens were sent to Mr. 

 Howard of the Agricultural Department at "Washington, and he 

 called them Pteromalus jiuparum. We do not know of this species 

 having been found before parasitic on the larva of this butterfl}^, 

 though another species, PUromalus vanessoi, Harris, with this habit 

 is recorded. 



