354 



COLLEGE ZOOLOGY 



Tropcea luna, the " tent-caterpillar," Clisiocampa americana, 

 and the silkworm moth, Bombyx mori. The silkworm moth 



(Fig. 286, C) is thoroughly 

 domesticated and, so far 

 as is known, does not occur 

 in a wild state. The silk 

 industry originated in 

 China many centuries B.C. 

 It did not become very 

 important in this country 

 until the nineteenth 

 century. There are now 

 about a hundred million 

 dollars invested in the silk 



FIG. 287. Order LEPIDOPTERA. Army- . i , r ,1 TT v j 



worm, Hcliophila unipuncta. a, adult, b, industries of the United 



larva, with eggs of a parasitic fly (tachinid) States. The moths lay 



on back, c, pupa or chrysalis. (From , . , , 

 Webster, Yearbook Dep't Agric., 1908.) 



paper provided for them. 



The larvae (Fig. 286, A) are fed principally on mulberry leaves, 

 and when about forty days old spin a cocoon (B) of a single 

 continuous thread averaging over a thousand feet long. In 

 the cocoon the larva pupates. 

 Silk is obtained by killing the 

 pupa with heat or boiling water, 

 then clearing away the loose out- 

 side floss, and unwinding the 

 thread. 



Among the important moths 

 of the family NOCTUID.E are the 

 army- worm, Heliophila uni- 

 puncta, the cotton-worm, Aletia 

 argittacea, and the boll-worm, Flo . 288 . _ Order LEPIDOPTEEA . 



Heliotkis armiger. The army- Spring canker-worm. a, male. 



worms (Fig. 287) are striped b ' fen } al( r c, larva, d, eggs- 



natural size and enlarged. (From 



caterpillars that feed on growing circ. 9, Bur. Ent., U. S. Dep't Agric.) 



