NYMPIIALINAE : PIIYCIODES THAROS. 637 



nearly or quite struiglit, and touehing each other" (Edwards). Mr. 

 Mead found the chisters to vary from 20 to about 150 eff^s. Mr. 

 Edwards at a hitcr date from 50 to 225. Recently an imprisoned female 

 laid for me on the under side of a leaf about three inches from the top of 

 the stalk a cluster of cgga, closely crowded in a mass, one side of which 

 was straight, lying against the midrib, the other an irregular curve, the 

 mass being about twice as long as broad. There were about one hundred 

 eggs in the cluster, most of them lying in a single layer about as elosely 

 crowded as possible, but the outer ones a little scattering ; on the top of 

 them was a second layer of about a quarter as many, also closely crowded, 

 but not quite so regularly erect, some being tipped a little, doubtless from 

 the irregularity of the base. In another case, fifty or sixty were laid, 

 closely crowded together but all in a single layer. In another instance an 

 imprisoned female laid seven scattering eggs on one leaf, none touching 

 the others. A day before hatching the eggs rapidly become discolored. 

 Mr. Edwards gives the period of the egg stage at from four to seven days. 

 At Cambridge mine have hatched in about eight days, and Professor Ham- 

 lin found the period ten days at Waterville, Me., in Julv. 



Food plant. The food plant of this most common butterfly was for 

 years a puzzle, and I have myself followed the females for many an hour 

 in the vain search for some sign of its oviposition, a much more diffi- 

 cult task with those which lay eggs in clusters than with butterflies which 

 lay but one egg at a time. Mr. T. L. Mead at last solved the problem, by 

 guessing at the Compositae (as they were the food plant of other Meli- 

 taeidi), enclosing groAving plants of a number of different kinds in a box, 

 and imprisoning in this artificial garden the female butterflies. In a few 

 days they selected Aster novae angliae, on Avhich to deposit eggs, and 

 this species seems to be their favorite food plant, though they will feed on 

 any asters, but not with equal freedom. Mr. Edwards once obtained 

 eggs laid by an imprisoned female on Chelone, but he did not raise them. 

 Miss Middleton (Rep. nox. ins. 111., x : 83) gives Actinomeris also as a 

 food plant ; not unlikely it may be forced to eat this, but it is hai'dly prob- 

 able that the female herself selects it. 



Habits of the caterpillar. In the only case observed by me, the 

 caterpillars in exposed eggs hatched and moved away before those in un- 

 derlying layers eft'ected their escape : and it would seem as if this must 

 need be the case. Not the slightest web of any kind is spun, not even in 

 crawling from the walls of their prison, which are less than half demol- 

 ished in their escape, many crawling out Avhen only the crown has been 

 bitten around, a little below the summit, and pushed back far enough to 

 permit exit, only to return to its place by its elasticity after the passage of 

 the prisoner. Xor do they eat their cast-off skins whether at the first or 

 second moult, but leave them lying like a spread mat on the leaf just 



