28 Journal New York Entomological Societv. [ vol. vi. 



serve them, and it was not until several days that the young were found 

 on the blades of timothy. On October ioth, however, they were found, 

 and at that time had precisely the appearance that French ascribes to 

 the larvae before first moult, viz., the two extremities of the body were 

 of a pinkish color while the intermediate portion was of a greenish hue, 

 which I ascribed at the time to the color of the food showing through 

 the almost transparent walls of the body. In this case, I believe the 

 egg stage was about twelve days, instead of five days, as observed by 

 Professor French, as the eggs had not hatched on October 8th, and the 

 larvae did not show the reddish stripes, which indicate the period fol- 

 lowing first moult, on October 12th, but did show them on the 14th. 

 This would give an egg period of twelve days, and the larval period to 

 first moult five or six days, instead of three, as Professor French found 

 it to be at Carbondale, Illinois. Was this difference due to latitude or 

 to the advanced season when riiy observations were made ? This will 

 certainly be an interesting question. The very young larvae have every 

 appearance of belonging to the Geometridae, and when feeding on the 

 blades of grass, eat the substance of the blades only, leaving the veins 

 and the epidermis almost intact. After the first moult they begin to 

 eat through the leaves and along the edges, causing cleanly cut notches. 

 The grass plant was now enclosed by a glass cylinder placed in a ver- 

 tical position, and the larvae, by jerking the posterior part of the body 

 while hanging to the grass blades by the feet, threw the excreta away 

 from them, and it could be observed in abundance on the inside of the 

 glass, where it had been caught and held by the moisture collected 

 there. If in any way disturbed, however, they hang by the penulti- 

 mate and anal pairs of feet and wave the body about frantically, and 

 then remain quiet, clinging by the three pairs of prolegs, the body 

 arched nearly in the form of the letter S, the anterior feet and legs bent 

 backward beneath the body, which is usually placed parallel with the 

 blade on which it is stationed, but not holding to or touching it. On 

 November 4th, some of the larvae were observed in the act of moulting, 

 the first time I had observed them to do so, though this was doubtless on 

 account of my not having been able to give them daily attention. It 

 will be observed that these larvae were now a few days less than a month 

 old. Professor French found the date of last moult to vary from 19 to 

 25 days from hatching. 



My larvae had now become reduced to six, and by the 19th of Novem- 

 ber, these varied so greatly in size that I was led to measure the lot, 

 and by so doing found that there were really two series, in point ot 



