INSECT PESTS OF OHIO SHADE AND FOREST TREES 267 



Distribution. — The insect is known to occur throughout the 

 Atlantic seaboard and extends to the West as far as the Great 

 Plains. 



Natural enemies. — Doctor Riley (34) reports the following list 

 of parasites of this species : Ophion macrurum Linn, Exorista 

 leucaniae, Kirk var. cecropae Riley, Chalcis mariae Riley and Cryp- 

 tus extramatis Cresson. In Ohio, woodpeckers are active enemies 

 of the species during the winter months, piercing the cocoon and 

 drawing out the pupal juices. 



Control. — Rarely is artificial control necessary. The simplest 

 method is picking off the large feeding caterpillars. Arsenical 

 sprays doubtless would also prove effective. 



THE POLYPHEMUS MOTH 



(Telea polyphetnus Cramer) 



Description. — Another member of the large silkworm group is 

 the polyphemus moth, known as the American silkworm because of 

 its particularly heavy silken cocoon. While numerous attempts 

 have been made to utilize the silk, none have proved commercially 

 successful. The moth measures more than 5 inches across its 

 spread wings. In color it is a beautiful light brown with a pur- 

 plish band near the outer margin of the wings and both fore and 

 hind wings bear large eyelike spots. The eggs are round, flat and 

 light brown, with a band of darker brown around the outer margin. 



The larva is a little less than 4 inches long, stocky in build and 

 thicker in the middle. In color it is a beautiful pea green with 

 brown head and with silvery-white ornamentations on the sides. 

 (See Plate XLII, Fig. 4.) 



The cocoon is dense, firm and usually with a leaf surrounding 

 it and securely cemented to the outer surface. The pupa within is 

 dark brown and not much longer than thick. 



Life history and habits. — The winter is passed in the cocoon 

 and the moths emerge in June to lay their eggs. The caterpillars 

 mature in August or September, spin up their winter cocoons and 

 transform to the pupal stage. 



Nature of work. — The feeding of the larvae is the only injury 

 done by this species, and while they possess tremendous appetites 

 and are quite capable of much injury if abundant, they rarely do 

 serious harm since they usually are very scattering. 



Food plants. — The polyphemus caterpillars attack a consider- 

 able number of trees, some of the more important being white oak, 

 scarlet oak, red oak, sycamore, soft maple, hickory, black walnut. 



