INSECT EHEMIES. Ill 



until it reaches the tail, forming a sort of cone, as at fig- 

 ure 94, /. As the caterpillars increase in size they enlarge 

 their houses upward, until the elongation makes their bags 

 so large and heavy they hang to one side, instead of being 

 upright, as at/. They are full grown about the end of 

 July when hatched the last of May or early in June. 

 The habit of the full-grown worm of letting itself down 

 by its silken threads, suggested the name of Drop-worm. 

 When they travel they extend the head and enough of 

 the body to use three pairs of legs, each provided with a 

 strong claw, while the five pairs of very short legs within 

 their case retain a strong hold with clinging hooks. 

 They moult four times while growing. At each time 

 they close the mouth of the sack, and retire for two days 

 to cast off their skins. In closing the bag, a hole is 

 always left at the end large enough to throw out their 

 excrement and their cast-off skins. The body is cylin- 

 drical and soft, and that portion usually concealed in the 

 case is lighter colored. At maturity they fasten their bags 

 securely to the twigs of the tree, instinctively avoiding 

 the leaf-stalk that will fall. Then they line them with 

 soft silk, and turn round, with their heads toward the 

 lower orifice, where they wait to cast their skins and be- 

 come chrysalids. Up to this change the sexes have been 

 alike in appearance ; but henceforth they are easily dis- 

 tinguishable. The male chrysalis has the form of ordi- 

 nary chrysalids, being about half the size of the female. 

 The female chrysalis has no sign of encased wings, legs, 

 and antennae, appearing as a naked, yellowish bag of eggs 

 with a ring of soft light brown hair near the tail. After 

 three weeks the male chrysalis works down to the end of 

 his bag, and, hanging half way out, bursts his skin, and 

 emerges as a moth with a black body and glossy wings, 

 as at d. The male is proportionally stout bodied, with 

 a long abdomen, and broadly pectinated antennae. The 

 female has neither wings nor legs. The bag-worm is 



