106 THE COMMONER BUTTERFLIES. 



under side of the leaves of the food-plant in dense patches 

 of from two to five tiers to the number sometimes of five 

 hundred; they hatch in eight or nine days. The cater- 

 pillars feed on sj^ecies of Celtis, the hackberry; they do 

 not devour the egg-shell, and are gregarious in their first 

 three stages, feeding side by side in rows, eating the leaf 

 from the tip backward, but leaving the stouter ribs; they 

 form a pathway of silk wherever they go; but construct no 

 concealment of any kind; after the third moult they dis- 

 perse and feed singly. The chrysalis state lasts fibout ten 

 days. The butterfly is a southern species and is therefore 

 found only in the southern part of our district, about as 

 far north as the Ohio River, but occurs in southern Iowa 

 and has been once reported from southern Michigan. It 

 is single-brooded, ajipearing on the wing in June and July, 

 and the caterpillars hibernate in fallen leaves and crevices 

 of bark at about the time of their third moult. 



The species is dimorphic, one form (proserpina) having 

 the upper surface of the hind wings, at least in the female, 

 obscured with brown, while in the other (clyton) it is not 

 so obscured. 



CHLORIPPE CELTIS— THE GRAY EMPEROR. 



(Apatiira celtis, Doxocopa lycaon, Apatura lycaon.) 



Butterfly. — Upper surface of wings sordid or gray fulvous, 

 marked much as in the preceding species, but with the lighter 

 spots of the outer half of the fore wings white and therefore very 

 conspicuous, a premargiual ocehus in the lower half of the wing 

 and, on the hind wings, a distinct sinuous black stripe between 

 the dark margin and the row of black spots. On the under sur- 

 face it differs in a similar way, and also in the larger, more oval, 

 more largely blue-pupilled ocelli of the hind wings, found also to 

 some extent (but usually white-pupilled) on the fore wings. 

 Expanse about 2 inches. 



Caterpillar. — Head green, witli four pale facial stripes, lateral 

 spines and the summits crowned by a long, apically forked, 



