148 ENTOMOLOGY. 



draws itself out of the rent. It stands on its feet for a few 

 minutes, while its wings exjiand, and then takes flight and 

 sails gracefully through the air on its broad wings. 



Figs. 175 and 176 illustrate the metamorphosis of the 

 Dana is archippus from the egg to the butterfly. The stu- 

 dent should try to repeat Riley's ob-ervations on the way 

 in which the chrysalis suspends itself by the minute curved 

 hooks of the abdominal spine or ere master. When about 

 to transform, the caterpillar stops eating and contracts in 

 length, also becoming thicker. It then spins a little tuft 

 of silk to the under side of whatever object it may select, 

 and entangles the hooks of its hind legs in the silk, as at C, a. 

 It then casts its skin, pressing it back to the end of the 

 body as at b. Quoting Riley's exact words: "The supple 

 and contractile joints of the abdomen are made to subserve 

 the purpose of legs, and by suddenly grasping the shrunken 

 larval skin between the folds of two of these joints as with' 

 a pair of pincers, the chrysalis disengages the tip of its 

 body, and hangs for a moment suspended as at c. Then 

 with a few earnest, vigorous, jerking movements it suc- 

 ceeds in sticking the horny point of its tail into the silk, 

 and firmly fastening it by means of a rasp of minute claws 

 with which that point is furnished." 



In most Lepidoptera the males emerge and fly about for 

 some time before the females. Darwin infers that the 

 adult males of most Lepidoptera generally exceed the fe- 

 males in number, " whatever the proportion may be at their 

 first emergence from the egg" (Descent of Man, i. 305). 



The " assembling" of moths is a curious fact. If a vir- 

 gin silk-worm moth be exposed in a cage, great numbers of 

 males will collect about the box. It is so with some beetles, 

 as the Pridnus ffrevicomis and probably other longicorns. 



The wings of the two sexes of Lepidoptera often differ 

 in venation, and usually in outline; while the males of 

 certain South American butterflies have tufts of hair on 

 the edges of the wings, and horny excrescences on the 

 disks of the hinder pair. The males of certain butterflies 



