16 BULLETIN 838, TJ. S. DEPARTMENT OF AGRICULTURE. 



Here the male larva proceeds to spin a cocoon, secreting cottony 

 wax from the small ducts which occur on both the dorsum and venter 

 of the body, turning over and over in the operation. The cotton se- 

 creted is finer than that secreted by the female larva, as would be 

 expected because of the smaller ducts on the male. 



It requires three or four days to complete the cocoon. After a day 

 or two of inactivity, the larva molts to a prepupa, pushing the cast 

 skin out through a slit which is in the rear end of the cocoon. 



MALE PREPUPA AND PUPA. 



The male from now on is without mouth parts, and during this 

 dormant period is an inactive creature, capable only of feebly waving 

 its front legs and wriggling its abdomen when disturbed. 



The male remains in this stage from 10 to 15 days, and with this 

 molt becomes a true pupa, greatly resembling the adult male. As in 

 the previous stage, the pupa is inactive. Normally the same length 

 of time is required for this stage as for the previous one. A few 

 pupse have been found hibernating in the colder Sierras. 



ADULT. 



When the pupal skin is cast, the male's wings are extended to their 

 full size and then folded, one over the other, upon its back. As soon 

 as the wax filaments have grown to their full length, which requires 

 from 30 minutes to several hours, the male backs out of the cocoon 

 and becomes very active. It immediately begins searching for a mate. 

 The length of life of the male is never more than one or two days 

 and death occurs very soon after mating. 



FEMALE. 



The color of the female becomes darker after the second and last 

 molt, and upon becoming heavily chitinized is a dark reddish brown. 

 After mating the body increases considerably in size, becoming nearly 

 globular. Inside the female's body may be found a large number of 

 eggs in different stages of development, The body still is covered 

 quite thoroughly with cotton and deeply hidden in the bark crevices. 

 Upon becoming an adult a new supply of coarser threads of wax is 

 excreted. After depositing the eggs, an act which covers a consider- 

 able period of time, the female shrivels and dies, nothing but the 

 chitinized skin remaining. If the host plant is still alive, this vacancy 

 is soon filled by a female of the next generation. 



SEASONAL HISTORY. 



(Fig. 3.) 



There is but one generation per year, the limits of which are not 

 very definite. The males appear in the fall, being most abundant in 



