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Report of the State Entomologist. 



209 



the summer brood. The caterpillars from these, feeding through 

 June, produce their moths in August From these, again, we have 

 the caterpillars which are so destructive to autumnal crops in 

 September and October, which pupate in the latter month, and pass 

 the winter in that stage. 



The larvae obtained from the eggs on August twentieth enable me 

 to give their features at an earlier stage than that previously given. 



When just from the egg, they measure one-twelfth of an inch in 

 length. The head is black, and the flesh-colored body bears rows 

 of rounded, black, setiferous spots — the superior four of which on 

 each segment form the " trapezoidal spots." The hairs are black. 

 The larva loops in walking, as only six of the prolegs are employed 

 in locomotion. 



Food-plants. 



In addition to the list of food-plants of this caterpillar (apparently 

 rather a general feeder on garden crops) given by Professor Kiley, 

 viz., cabbage, turnip, beet, spinach, strawberry, asparagus, honey- 

 suckle, mignonette, asters, lamb's quarters (Chenopodium album), 

 may be added from my own observations, sweet pea, field pea, currant, 

 and buckwheat. 



On July 3, 1884, Mr. Groff sent from the Agricultural Experiment 

 Station at Geneva, larvae of from three-eighths to one-half inch long, 

 which may have undergone two molts, that were infesting, to a serious 

 extent, peas and cabbage on the station grounds. For mention of a 

 severe attack by the caterpillars on a mangold crop, in St. Lawrence 

 Co., N. Y., in 1883, see my 2d report. 



Bemedies. 



It is comparatively easy to deal with this insect while in its early 

 stages when it is of social nature and feeds in companies. At this 

 time the leaves containing them may be plucked and crushed by 

 the foot. 



Later, they may perhaps be best destroyed by pyrethrum powder, 

 to which they are quite susceptible, as shown by the following 

 experiments made: 



Undiluted pyrethrum was scattered over five larvae, less than half- 

 grown. They were very soon in violent convulsions, squirming and 

 twisting as if in great agony and discharging a green liquid from the 

 mouth. In a half hour's time they were unable to turn from one side 

 to the other, and only gave contractile movements. In three-fourths 

 of an hour motion had nearly ceased. In one hour and a half they 

 were motionless and seemingly dead. 



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