43 



whether these insects really possessed any such instincts, the inference 

 having been that one variety was as acceptable to them as another. 

 Bearing upon this point I have obtained some interesting information, 

 which, though by far too slender a thread on which to hang a positive 

 assertion, yet forms sufficient grounds for a suspicion that the species 

 may possess some exceedingly fine instincts regarding plant tissue. 



In the month of September, 1888, a field of oat stubble on the exper- 

 iment farm was subdivided, two plats each several acres in extent being 

 sown, the one to velvet chaff and the other to Michigan Amber wheat. 

 Between the two was a narrow strip comprising a mixture of both 

 varieties. From the beginning of preparation of the ground to the end 

 of harvest this year all conditions excepting seed were exactly the same. 



The attacks of these larva3 were quite severe during June, and on the 

 14th of this mouth an examination of the plats above mentioned devel- 

 oped the fact that in the velvet chaff the destroyed heads outnumbered 

 those in the Michigan Amber in the proportion of about four to one. 

 Furthermore, the narrow strip of mixed grain intervening showed very 

 much the same feature. I confess that I am unable to detect any rea- 

 son for this difference in the severity of the attack other than in the 

 nature of the straw ; that of the velvet chaff being under ordinary con- 

 ditions a few days earlier in maturing, yet it is known among farmers 

 as possessing a softer straw than the Michigan Amber, which fact pre- 

 supposes the tissue of the stem immediately above the upper joint to 

 be to a corresponding degree more tender and juicy at the time of ovi- 

 position by the females. 



THE WESTERN STRIPED CUTWORM. 

 (Agrotis herilis Grote.) 



The present year has been conspicuous for the severity of cutworm 

 attacks, especially in corn-fields, the most abundant and pernicious 

 species thus engaged being the one under consideration. Ordinarily 

 we look for these dusky, semi subterranean destroyers in fields of re- 

 cently broken grass lands, but this season their ravages were not to be 

 limited by any such proscribed bounds, and old lands suffered with the 

 new. 



On the 28th of May I visited a field of corn a few miles out of the city 

 of La Fayette, which had been nearly ruined by cutworms, notwith- 

 standing the present was the seventh consecutive crop of corn which 

 had been planted on this ground. In fact, so abundant were the pests, 

 that from amass of dried weeds and earth, covering a couple of square 

 feet, and which had been left by the plows, I took 36 individuals, and 

 a clod a few inches away concealed 5 more ; the whole number evi- 

 dently belonging to the same species. 



The only apparent cause for this congregating in corn-fields, and in 

 this one in particular, is that during the ovipositing season last sum- 



