46 



color, tinged low down on each side with greenish-gray, and is everywhere 

 sprinkled over with black points and dots. Along its back is a row of ten 

 or eleven oval or diamond-shaped white spots which are similarly sprinkled 

 with black points and dots, and are placed one on the fore part of each seg- 

 ment. Behind each of these spots is a much smaller white spot, occupying 

 the middle of each segment. The intervening space is black, which color 

 also forms a border surrounding each of these spots, and on each side is an 

 elevated black dot from which arise usually four long black hairs. The 

 hind part of each segment is occupied by three crinkled and more or less 

 interrupted pale orange-yellow lines, which are edged with black. And on 

 each side is a continuous and somewhat broader stripe of the same yellow 

 color, similarly edged on each of its sides with black. Lower down on each 

 side is a paler-yellow or cream-colored stripe, the edges of which are more 

 jagged and irregular than those of the one above it, and this stripe also is 

 bordered with black broadly and unevenly on its upper side and very nar- 

 rowly en its lower side. The back is clothed with numerous fine fox-colored 

 hairs, and low down on each side are numerous coarser whitish ones. On 

 the under side is a large, oval, black spot on each segment except the ante- 

 rior ones. The legs and pro-legs are black and clothed with short whitish 

 hairs. The head is of a dark bluish color flecked with numerous black dots 

 and clothed with short blackish and fox-colored hairs. The second segment 

 or neck is edged anteriorly with cream white, which color is more broad 

 upon the sides. The third and fourth segments have each a large black spot 

 on each side. The instant it is immersed in spirits the blue color of cater- 

 pillar vanishes and becomes black. 



By referring to Plate III, fig. 2, the difference in the dorsal 

 markings of the two common species of tent-caterpillars will be 

 plainly seen. The caterpillar on the left is an apple-tree tent- 

 caterpillar, the other two are forest tent-caterpillars, the one on 

 the right being a lateral view. All are nearly full-grown and 

 are natural size. 



The cocoon. — The cocoons are made of coarse white silk which 

 soon becomes discolored by the weather. In size and shape they 

 closely resemble those of the apple-tree tent- caterpillar described 

 on pages 286-287 of Bulletin 152 of this Station, but are some- 

 what more loosely woven and have less of the yellowish powder. 

 In the vicinity of Geneva the spinning of the cocoons began last 

 season about the last week in May and continued until the middle 

 of July. 



Although it has been considered one of the characteristics of 

 this species to utilize a leaf in making the cocoon there were many 

 exceptions last season, for they were found in great numbers upon 



