208 TENTH ANNUAL REPORT. 



for a common name has not been recognized. When full 

 grown this caterpillar is nearly two inches long, and of the 

 general form represented in a of Plate I; the head is reddish 

 brown, while the body is striped longitudinally with black, 

 yellow, and whitish. Near the hind end there is a prominent 

 reddish hump, the presence of which has led to the proposal 

 of the common name mentioned above. 



These caterpillars feed upon the leaves of the various spe- 

 cies of oak, eating the blades and leaving the midribs. In 

 this process good sized pieces of the leaves are commonly 

 detached to fall to the ground, where they were very abun- 

 dant in the infested woods. When the caterpillars become 

 full grown — from the middle to the last of September — they 

 descend to the ground, where beneath the fallen leaves they 

 pupate in a slight cocoon. The pupa is brown, and of the 

 shape represented in Fig. h of the plate. The following 

 spring the pupae develop into greyish moths, similar to the 

 one represented in c. These moths rest during the day upon 

 oak twigs, being rendered inconspicuous by their resemblance 

 to a growth on the twig. 



These red-humped oak caterpillars are seldom injurious. 

 One reason for this is to be found in the fact that they are 

 greedily devoured by the common ruffed grouse or partridge, 

 which frequents the open woods where the caterpillars occur. 

 In a study of the food of this bird the present season, Mr. Ned 

 Dearborn of this college has found that a large part of the 

 food in September consisted of these caterpillars, as many as 

 sixteen of them being found in n single stomach. 



During the early summer inquiry was repeatedly made con- 

 cerning two of our largest and most beautiful moths, which 

 seemed either to be unusually abundant, or else to attract 

 more than ordinary attention. The first of these is the large 

 dark brow^n moth, the side view of which is represented in 

 Fig. 13. When its wings are spread they commonly expand 

 about five inches from tip to tip, the body of the insect being 

 nearly an inch and a half long. On the front end of the 

 body are two large feathery feelers or antennae. On each of 

 the wings near the middle there is a whitish or brownish ores- 



