'Nkw York Agricultural Experiment Station. 301 



tween the third and fourth molts. The periods of molting and the 

 markings were observed and recorded by C. V. Riley^^ in 1870. 

 The follo'wing descriptions do not differ essentially from those 

 given by him. The caterpillars just after leaving the eggs meas- 

 ure on the average 2 mm. in length. They are dull black in color 

 with long grayish-white hairs arising from numerous minute 

 tubercles. In a few days there is a slight change in color. The 

 middle of the body becomes lighter, taking on a brownish tinge, 

 while the extremities remain darker. The tubercles also become 

 more distinct and a dark interrupted line conspicuous along each 

 side. These markings become more prominent as the time for the 

 first molt approaches. 



TJie first molt. — The first molt occurs from ten days to three 

 weeks after the caterpillars emerge from the eggs, the variation 

 in time probably depending upon the abundance of the food sup- 

 ply. Immediately after the first molt they measure about one- 

 half inch in length. There are two pale yellowish sub-dorsal lines 

 bordering the dark lines above referred to. These lines become 

 more conspicuous as the time for the second molt approaches ; the 

 dorsal spots are also indistinctly seen. 



The second molt. — This molt occurs from a week to ten days 

 after the first when the length is about three-fourths of an inch. 

 A row of eleven cream-white somewhat diamond shaped or club- 

 shaped spots extends the full length of the back. Also as Dr. 

 Riley states in the reference above given : " The upper pale line 

 becomes yellow, the lower one white, and the space between them 

 bluish." 



The third molt. — The third molt occurs about a week to ten 

 days after the second. The caterpillars measure about one inch 

 in length. There is little change in the markings except that they 

 become more distinct. 



The fourth molt. — Between the third and fourth molts is the 

 most rapid-growing period of the larval life. After the fourth 



iTAmer. Ent. and Bot., 2: 2G2. 



