96 NEW YORK STATE MUSEUM 



leaves, lining them with silk, and inclosing them with a mass of 

 silken threads. These tents [pi. 1, fig. 7] are so firmly secured to 

 the twigs that they can not be removed without considerable force. 



The young caterpillars emerge from their winter retreats 

 before the leaves begin to appear, often attack swelling buds and 

 complete their growth in the early part of June, when they trans- 

 form to pupae. The full grown caterpillars [pi. 1, fig. 3] range 

 from 1 inch to I14 inches in length. The pale brown head is 

 mottled with dark brown and has reddish brown hairs scat- 

 tered over its surface. The body is dark brown or black 

 with numerous fine, dull orange or gray spots over the surface, 

 which are most pronounced on the second, third and fourth 

 segments. Long reddish brown, finely barbed hairs arise from 

 all the tubercles, and white branching hairs from the upper side 

 of the latter tubercles on segments 4 to 12 inclusive. These 

 white hairs form elongated white spots along each side and are 

 one of the most striking characteristics of this caterpillar. The 

 subdorsal and lateral tubercles on segments 4 to 12 inclusive 

 are covered with fine, short spines of uniform length. There is 

 a bright red retractile tubercle on the top of the 10th, and also 

 one on the 11th segment. 



The pupae are % inch in length, dark brown in color and with 

 fine, yellowish brown hairs [pi. 1, fig. 4] scattered over the 

 surface. 



Habits of the caterpillars. The following account of the habits 

 of these caterpillars is taken from a bulletin by Fernald and 

 Kirkland, and is as follows: 



The young caterpillars of the brown tail moth, after hibernat- 

 ing in the tents which they construct at the tip of the branches, 

 emerge in the spring and feed downward towards the main 

 branches and trunk, leaving the naked twigs bearing the gray 

 tents at the ends, a conspicuous evidence of the presence of this 

 insect. They eat the entire leaf except the midrib, and, in leaves 

 having strong ribs, like those of the sycamore maple, all the 

 larger ribs are left untouched. \A'hen the caterpillars are numer- 

 ous they devour not only the buds, leaves and blossoms, but even 

 the green fruit. 



The caterpillars are quite gTCgarious up to the later stages of 

 their growth, when they disperse to some extent; but when they 

 occur only in moderate numbers, they retain their gregarious 



