THE ENTOMOLOGIST. Ill 



part, lives in a tube of silk, which it builds and extends often 

 several inches beyond the trunk or stem in which it burrows, 

 and from which it often, especially when young, issues to 

 feed. In this, again, it approaches the Hesperians, which 

 are partial concealers, and live, when not feeding, within 

 silken cases or tubes constructed among the leaves of their 

 food-plants. 



The pupie of the Castnians, like those of all Heterocerous 

 borers known to me, are, according to authors, armed with 

 rings of minute spines on the hind borders of the abdominal 

 joints — the spines serving a very useful purpose in assisting 

 the pupa out of its cocoon. Heterocerous borers also pupate 

 in a more or less perfect cocoon, made either within or 

 without the burrow; and, in the issuing of the imago, the 

 mesothoracic covering generally collapses, the leg-cases 

 become unsoldered, and those of the antennae are always 

 separated and often curled back over the head in the exuviura. 

 The Hesperians pupate within the silken cavity occupied as 

 larva, or else in a separate slight cocoon : the pupa is 

 generally attached to a silken tuft by the hooks of the 

 cremaster, and sometimes by a silken girth around the middle 

 of the body besides : it is not unfrequently covered with a 

 slight powdery bloom, and is characterized by the prominence 

 of the prothoracic spiracle : the exuviura more nearly retains 

 its form, the leg-cases remaining soldered, and even those of 

 the antenna being rarely separated. In not having a well- 

 formed cocoon, in being covered with bloom, in the characters 

 of the exuvium, in the conspicuity of the prothoracic spiracle, 

 but more particularly in the want of minute spines on the 

 borders of the abdominal joints. Yuccas is again Hesperian 

 and not Castnian. Indeed, except in the broader anal flap, 

 densely surrounded with stiff bristles, in place of an apical 

 bunch of hooks, in the smaller head and larger body, it 

 resembles Nisoniades in general form, colour, and texture. 



The typical Castnians, in the pertect state, have the wings 

 large with loose and venj lartje scales, and the hind-wings 

 invariably armed, at costal base, with the long stout spine, or 

 spring, which serves to lock the wings in flight by hooking in 

 a sort of socket beneath the primaries, and which is so 

 characteristic of the Heterocera. The venation resembles 

 more nearly that of the Ilepialians, and is totally unlike that 



