New York Agricultural Experiment Station. 329 



viously stated the beetles feed voraciously on the new growth, pre- 

 ferring the tender bark, but also feeding upon the leaves, and 

 frequently devouring the young shoots before they have fairly 

 started. 



The egg. — Egg-laying begins about the 10th to the 15th of May 

 and may continue for a week or more. The eggs are deposited 

 in groups, usually on the under surface of the willow leaves, but 

 they were frequently found upon blades of grass or leaves of 

 weeds growing in the willow rows. Each egg is firmly fastened 

 on end to the leaf and usually in a slightly slanting position as 

 shown at Plate XX, on the left of Figure 1. These groups vary 

 in the number of eggs contained. In about 15 examined the num- 

 ber varied from 25 to 52. The average number is about 45. 



The eggs are light lemon-yellow in color, turning to a deep 

 salmon just before hatching. They are elongate-oval in outline 

 and vary in size from 1.35 mm. by 0.63 mm. to 1.47 mm. by 0.84 

 mm. The shell is smooth, thick and leathery. 



Period of incubation. — The period of incubation is usually 

 from 10 days to 2 weeks. This was the period for 1894, 1895 

 and 1896. Last spring was an exception, as few of the eggs 

 hatched within 20 days. 



The larva. — When first hatched the larvge measure from 1.05 

 mm. to 1.11 mm. in length. The diameter of the head is 0.6 mm. 

 and that of the body 0.54 mm. on the anterior half, tapering to 

 0.21 mm. at the last abdominal segment. The entire body is black 

 or very dark brown. When full grown they measure, on an 

 average, about 8 mm. in length. The width of the head is 0.75 

 mm. and of the body, on the anterior half, 2.5 mm. tapering to 

 about 0.6 mm. on the last abdominal segment. The body is of a 

 dirty yellowish color, the head a dark brown and the legs black. 

 A double row of dark brown spots, two on each segment, extends 

 along the upper surface of the abdomen. In a line with these is 

 a row of black tubercles on each side which, when the insect is 

 disturbed, emit drops of white milky fluid, of a strong pungent 

 ' odor, which may be drawn back when the threatened danger is 



