1442 THE BUTTERFLIES OF NEW ENGLAND. 



on Desmodium dillenii and raised the caterpillar on it. I have also had 

 egffs laid on m-ass blades beside clover. 



Habits of the caterpillar. On emerging from the egg the larva 

 usually devours only the upper half of the shell, then travels to another 

 leaf and prepares a nest j it first bites two narrow, parallel, generally 

 somewhat arcuate slits about 6 mm. apart, as many deep and as wide as its 

 body, near the middle of one side of the leaf; the piece thus partially 

 detached is then bent over and attached by silken cords to the upper sur- 

 face and the caterpillar crawls within, secure from observation and the 

 sun's rays ; similarly constructed retreats answer its purpose as long as the 

 leaf is large enough for the growing bodies, but afterwards they are appar- 

 ently constructed like those of the mature E. tityrus. It is as cleanly in 

 habits as the latter species, always retreating a few steps to the edge of 

 its abode and elevating the terminal segment slightly to snap away its 

 ejectamenta. When placed upon fresh leaves it never ventures a step 

 without lining the leaf with silk, moving its head from one side to the other 

 as if it were searching for something between its front legs ; while at its 

 meals it retreats slowly, eating with its head close to its hinder extremity 

 and devouring the leaves close down to the midrib ; both when eating and 

 when moving about, the head has always a tremulous motion. 



Pupation. Cocoons constructed in captivity were made by fastening 

 together clover leaves by a few strong, silken threads, so as to form a 

 cell, scarcely longer than the chrysalis, but several times its size ; the 

 chrysalis was entirely concealed from view by the leaves, and the threads 

 supporting the cremaster were pretty closely appressed to the end of the 

 cell ; these threads cross each other like an X, each thread being 8.5 mm. 

 long and crossing the other in the middle, into which the crochets of the 

 cremaster are plunged ; after forming the Y-shaped thread, upon which the 

 body is to recline, the caterpillar passes it beneath its body at the suture be" 

 tween the first and second abdominal segments ; afterwards, just before the 

 change of skin, it will be found between the second and third thoracic seg- 

 ments ; the stem of the Y is 4.25 mm. long, or just as long as either arm 

 of the X, and the forks each 6.5 mm. long; the chrysalid reclines on its 

 ventral surface. In other cases, however, the threads at the hinder extremity 

 also formed a Y like that of the front but with stem and limbs of similar 

 length. 



Life history. It is double brooded in the north passing the winter in 

 the chrysalis state. It first appears as a butterfly toward the end of May, 

 rarely earlier than the 24th* and usually not until the 27th or later. It 

 becomes abundant in about five or six days, but the male is always 

 so much more abundant than the female, that even toward the middle of 

 June, when the latter is laying eggs in large numbers it is outnumbered 



* I have taken f emaleB at this date. 



