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SOME STUDIES OF THE CLOVER HAY WORM. ASOPIA COSTALIS. 



By F. M. Wkkstkk, S2>ecial At/etit. 



Although much has beeu written of this insect, yet, so far as the 

 writer has been abh^ to gather from the bterature to which we haAe liad 

 access, Htth' if anything has been h^arued of its habits since it was 

 studied by Dr. Riley, as portrayed in his Sixth Report on Insects of 

 Missouri, p. 102. 



Late in April of the present year we received a number of these 

 larvae from Prof, W. I. Chamberlain, of Hudson, Summit County, Ohio, 

 with the statement that they were destroying hay in that neighborhood. 

 In accordance with instructions from Professor Riley we visited the 

 ftirm of Mr. Chamberlain on April 27, in order to investigate the matter 

 and see if some means could be de\ised whereby the pest could be de- 

 stroyed. 



On arriving at our destination we found that a stack of about 20 tons, 

 standing in the open field, had been damaged fully 50 per cent, although 

 the hay was fully three-quarters timothy. About 5 tons of this hay was 

 handled over and re-stacked beside the old site, in the mean time being 

 thoroughly dusted with a mixture of 10 pounds of powdered pyrethrum 

 thoroughly mixed in 50 pounds of fl(mr. This was done with the un 

 derstanding that the whole stack was to be removed in a short time, 

 when the results of the application could be ascertained. A small 

 quantity of hay thus treated and i)iled up to one side was examined 

 next day, and a niajority of the larvjie were found to have been de- 

 stroyed. The stack, however, contrary to our expectations, was allowed 

 to stand for nearly six months, when of course all Tiope of learning any- 

 thing of the effect of the exjieriment had long before vanished. The 

 result, though admitted a failure in this case, demonstrated the practi- 

 cability of the measure, and the smaller experiment gave evidence of 

 its efficiency. Other farmers in the vicinity reported serious losses 

 through the same insect, ami in some cases the hay had been so badly 

 injured that it had been burned on the ground, and this, too, as early 

 as late September or early in October of the previous year. 



A great number of larvae were taken from ]Mr. Chamberlain's hay, and 

 placed in breeding cages. These continued to feed on the dry hay for 

 a considerable time, pupae being first observed on May 25. Growing 

 clover plants were now transplanted to the breeding cage. Moths is- 

 sued from cocoons on June 12, and also on later dates. To all appear- 

 ances the eggs were placed in the heads of the clover, which, with the 

 rest of the i)lant, was kept alive and growing. On July 1, young larvae, 

 some very small, others half-grown, were found in the heads now turn- 

 ing brown but not dead, and the leaves being green. August (i, pupae 

 and larvae, both partly and quite full-grown, were taken from the cage, 

 and two days later adults also began to emerge. These adults were 



