202 THE BUTTERFLIES OF NEW ENGLAND. 



go their tranformations in a cocoon, generally made in large part of dried 

 leaves and other foreign matters, a light, fragile affair it is true, but still 

 unquestionably a cocoon. One or two other butterflies also make a slight 

 cocoon wherein to change to chrysalis, and these few instances, such as 

 Parnassius and Zegris, are found only in the family Papilionidae which 

 follows directly after the skippers. A single instance, however, has 

 recently been brought to light by Mr. W. H. Edwards in which an Erebia, 

 a species of Satyrinae, makes what may possibly be called by courtesy a 

 slight cocoon, by weaving a few grass blades together. 



The skippers, however, do not lie loosely in their cocoon as do the pupae 

 of moths, but spin at either end a Y-shaped shroud, into the centre of one 

 of which they plunge their hooked tail, while in the upper loop of the other, 

 they rest their body, changing the form of the upper arms of the Y from a 



V to a U. It is, however, often difficult to distinguish the form of the 



Y in the shroud into which the tail is plunged, as it is much smaller than 

 the other, and often more or less mixed with the threads which form the 

 end of the cocoon proper. Now when we reach the next family, the 

 typical butterflies (Papilionidae), the cocoon, save in the exceptional 

 instances mentioned, is lost ; while the silken attachments of the chrysalis 

 still remain, modified to suit the circumstances. Instead of the Y-shaped 

 band, wherein to plunge the tail, a carpet of silk is woven upon some 

 branch, into the midst of which the hooks are thrust, while the omission 

 of the stem of the other Y leaves a U-shaped loop or girt about the 

 middle. Sometimes at least, among the few instances in which a cocoon 

 itself is spun, the chrysalis within is still attached to the objects about 

 it, in the same way as is normal to the other members of the family. 

 But in other instances the published notices concerning this point are too 

 vague to allow definite statement. To accommodate the chrysalis thus 

 hung next a solid substance, instead of in the middle of an oval cell, the 

 segments of the abdomen must curve upward toward the ventral line (for 

 the chrysalis lies back downward), and thus the ventral line becomes 

 straight, while the dorsal is strongly arched. This condition of things is 

 perpetuated and often intensified in the next higher family, the gossamer- 

 winged butterflies (Lycaenidae) , which differ in this respect from the typi- 

 cal butterflies only in the closer binding of the girt around the middle. In 

 the highest family, the brush-footed butterflies (Nymphalidae), the girt 

 around the middle is lost and the chrysalis hangs suspended by the tail 

 alone. The chrysalis in this instance usually hangs perpendicular or 

 nearly so, but in a few instances the cremaster, or special development 

 of the last ventral segment for the attachment of the anchor-like hooks, 

 is elongated, and has hooks attached not only at the tip but down the 

 sides, thus enabling the chrysalis to remain rigidly horizontal or almost 

 horizontal, although attached only by the hooks at the tip of the abdomen. 



