160 THE COMMONER BUTTERFLIES. 



Under surface dark fuliginous, with the vitreous spots of the 

 fore wings repeated and a cinereous apex. Expanse about If 

 inches. 



Caterpillar. — Head with summits rounded and slightly ele- 

 vated, ferruginous brown with pale vertical streaks, or piceous 

 marked with ferruginous. Body naked, briefly pilose, pale green 

 with pale yellowish lateral lines and sprinkled profusely with 

 white dots. Length more than 1 inch. 



Chrysalis. — Dull olivaceous green, much infuscated, abdomen 

 pinkish brown, mottled faintly with pale dots, the rest as in the 

 preceding species. Length somewhat more than ^ inch. 



Probably found over the whole of our region, but not 

 yet noticed in the northernmost portions; it occurs mostly 

 in shady roadsides by woods and is strong, rapid, and 

 restless in fliglit, often flying in little circles as if about to 

 alight and then darting ofl: again. It hibernates as a full- 

 grown caterpillar and changes to chrysalis before vegetation 

 has started. It first appears as a butterfly early in May 

 and continues to emerge from the chrysalis throughout the 

 month, after spending sixteen days or more in chrysalis; 

 by the middle of June it has disappeared. It is possible 

 that there is a second brood, as fresh specimens have been 

 taken in the latter half of July ; but if so, it is but a small 

 one and the insect partly single-, partly double-brooded, 

 most of the caterpillars of the first brood remaining un- 

 changed until the succeeding year. The eggs, which are 

 shaped as in the preceding species with from eleven to 

 fourteen vertical ribs, more elevated above than in T. 

 htcilius, are yellowish green in color, changing afterwards 

 to blood-red ; they are laid singly on the upper surface of 

 tender terminal leaves and hatch in about a week. The 

 caterpillar feeds upon willows and poplars, and on emerging 

 from the ^gg eats only the crown; it constructs a flap-nest 

 like the last species, the flap being at first folded downward, 

 later ones upward; when very young it eats only the 

 parenchyma of the surface of the leaf near its nest; later 



