354 



COLLEGE ZOOLOGY 





Tropaa -luna, the " tent-caterpillar," Clisiocampa amcricana, 



and the silkworm moth, Bombyx niori. 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 

 industries of the United 

 States. The moths lay 

 their eggs on cloth or 

 paper provided for them. 



The larva? (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 



argillacea, and the boll-worm, 



Heliothis armiger. The army- Spring 



worms (Fig. 287) are striped 



FIG. 287. Order LEPIDOPTEEA. Army- 

 worm, Heliophila unipuncla. a, adult, b, 

 larva, with eggs of a parasitic fly (tachinid) 

 on back, c, pupa or chrysalis. (From 

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



_ Qrder LEPIDOPTERA . 



canker-worm. a, male. 



<' 



ndari 

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



