1142 THE BUTTERFLIES OF NEW ENGLAND. 



idly tapering ; claws stout, strongly curved at apex, finely pointed. Prolegs stout, 

 blunt, very short ; the hooklets from twenty to thirty in number, arranged somewhat 

 irregularly in a double arcuate row, moderately slender, tapering, slightly arcuate and 

 bluntly pointed. 



Chrysalis. Body very slender and attenuated, formed of two elongated, uniform 

 cones obliquely united at their bases at the point where the median girt is placed ; no 

 marked distinction between the head and thorax, but the dorsum of the thorax slightly 

 elevated. Frontal projection continuous with the body, forming a long, irregular, 

 tapering, bluntly pointed cone as long as the wing cases. Tongue case terminating 

 shortly before the antennae which extend to the tip of the wings, so that if the position 

 were reversed the chrysalis would rest on the antennal tips. Here the wing cases 

 are bent nearly at a right angle, but are rounded. The wing cases have only a slight, 

 rounded, dorsal carina scarcely noticeable, extending forwards to the basal wing tubercle 

 which is otherwise scarcely distinct. The dorsal portion of the abdomen forms an 

 angle of nearly 150° with the anterior half of the body. The abdomen is rounded, 

 slightly compressed, with no lateral ridge whatever, and tapers more rapidly in the 

 apical than the basal half. Cremaster as in Euchloe. Spiracles transversely short 

 ovate, slightly elevated, sublenticular, in a large, smooth, circular field. 



This genus, with three species, is found on both sides of the continent of 

 North America between the 35th and 40th parallels and reappears in east- 

 ern Asia at the same latitudes. A single species is found in Japan and 

 one on each half of the American continent. The closely allied genus 

 Euchloe, much more abundant in species, represents the genus in the north 

 temperate parts of the Old World and is also well supplied with species in 

 the western half of our own country.* 



The butterflies are rather small, with subfaicate fore wings, all the wings 

 white above, the outer border touched with black at the nervure tips, es- 

 pecially on the fore wings ; the fore wings have also a black spot at the tip 

 of the cell and in the male the whole apex is often orange. Beneath they 

 are white, the apex of the fore wings and the whole of the hind wings 

 heavily marbled with greenish brown and black. 



The insects composing this genus are comparatively little known, but 

 the earlier stages of our American species have been described in whole or 

 in part. The species are single brooded and appearing very early in the 

 season fly but a short time. They frequent open woods. The hottest part 

 of the year as well as the whole autumn and winter is thus spent in the 

 chrysalis. 



The eggs are slender, tapering at either end but especially above, the base 

 broadly and the summit narrowly truncate, with a dozen or fifteen sharp 

 vertical ribs ; they are laid on the flower stocks of slender Cruciferae which 

 mature early and disappear entirely after fruitage. 



The young caterpillars are slender, pale green with ranged clubbed hairs 

 on the body, as long as the segments. The mature caterpillars are dark 

 green with pale dorsal and stigmatal bands, a very broad spotted head, 

 sparsely but distinctly papillate, and, besides being covered with sparse pile, 



* In this statement 1 have followed Kirby's his Catalogue of diurnal Lcpidoptera, without 

 division of the species of Anthocharidi, in critical examination of all the forms. 



