526 NEW YORK STATE MUSEUM 



American silk worm 

 Tclca polyphoints Hiibn. 



A very large, pea-green, brown-headed, fleshy caterpillar with small, reddish brown 

 tubercles with silvered bases, occurs in midsummer on the foliage of a great variety of 

 plants. 



This, one of the largest of our native caterpillars, is frequently known 

 as the American silk worm on account of its dense silken cocoon, and vari- 

 ous attempts have been made to use the silk in a commercial way. It, like 

 other large forms, is not abundant as a rule, and only under exceptional 

 conditions does it become destructive. The nearly full grown caterpillar is 

 a beautiful object with its reddish brown tubercles silvered at the base and 

 ornamented at the tip with white hairs. These present a striking contrast 

 to the delicate pea-green color of the body. The head is a dull brick-red 

 and the anal plate is margined with maroon. The spiracles or breathing 

 pores are a delicate salmon color and the thoracic shield may be bordered 

 anteriorly with yellowish green. 



The adult is a dull ocher yellow moth with its wings, shaded with innu- 

 merable blqck particles, extending 5^ inches from tip to tip. The larva 

 may be found on a considerable number of food plants, it having been 

 recorded by various writers on oaks, hickories, black walnut, chestnut, elms, 

 maples, poplars, willows, birches, witch-hazel, linden, and a number of other 

 plants. It is never abundant enough so that repressive measures are 

 necessary to prevent serious injury. The moth is illustrated on plate 42, 



figure I. 



Luna moth 



Tropca luiui Linn. 



A stout, apple-green caterpillar about 3 inches long, with six rows of small, pink 

 hair-bearing tubercles, occurs in midsummer on a variety of trees. 



This giant caterpillar is never present in numbers sufficient to cause 

 material injury, yet the large size and exquisite beauty of the adult makes 

 it an object of general interest. The larva is a general feeder, having 

 been recorded on walnut, hickory, oak, butternut, chestnut, sweet gum, 



