New York Agricultural Experiment Station. 369 



to minute buckets with the covers on and without handles. The 

 shell is smooth and tough and the inside has a bluish tinge. 



The eggs are usually laid before the middle of July. It is not 

 unusual to find them about Geneva before the tenth. Each fe- 

 male deposits all of her eggs in one mass on any of the smaller 

 twigs, forming a thimble which may or may not reach clear around 

 the twig. The eggs are placed on end close together, cemented 

 and covered to the depth of about one-sixteenth of an inch by a 

 thin frothy glue of a light brown color. This glue soon hardens 

 into a tough but somewhat brittle covering, which has a brilliant 

 surface. The whole mass is somewhat oval, partly 'due to the 

 fact that the eggs on the margins of the mass are placed in an in- 

 clined position. 



The number of eggs in a single mass or thimble varies. The 

 number is usually placed at from 150 to 250. A number of egg 

 masses on peach and apple twigs examined by the writer contained 

 on the average about 223 eggs each. At Plate XXXI, Eig. 1, two 

 egg masses are shown natural size. Fig. 2 shows one of the 

 masses enlarged with the frothy covering removed to snow arrange- 

 ment of the eggs. Fig. 3 shows an old egg mass enlarged from 

 which the caterpillars have escaped. 



Period of incubation. — As above stated the eggs are usually laid 

 before the middle of July. The larvae are fully formed within the 

 eggs before or during the fall. The exact time was not observed 

 but eggs examined early in November contained fully developed 

 larvse. The larvse come forth early in the spring. In 1897 and 

 again in 1898 eggs under the writer's observation hatched about 

 the middle of April. The period of incubation then, counting the 

 time that the developed larvse remain in the egg, is between 8 and 9 

 months. 



The larva. — Last year in orchards about Geneva the young 



larvae were hatching April 18. They were quite common and 



building nests 5 days later. The newly hatched larvse measured 



1.7 mm. in length. They are dull black in color and are sparsely 



24 



