74 



[NJUEIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



waxy threads around the margin and a row down the middle of the 

 dorsum. The antenna are three-jointed. In the spring (April) the 

 entire body is covered with the white cottony material, as shown in Fig. 

 58. At tliis time the color changes to a reddish-brown. Fully-mature 

 specimens vary from 1-30 to 1-25 inch and three fourths as wide. The 

 eggs are oval and light yellow. The pupae are first rusty-brown, becom- 

 ing darker with age. The dorsum is covered with white powder and 

 dark, glandular spots. On the abdomen there are six longitudinal rows 

 of these glands from which the cottony covering is secreted. The winged 

 tenia les are also reddish-brown with black head and thorax and dusky 

 five-jointed antennae and legs. The bodies are covered with rather 

 dense white cottony threads, allowing only the wings to show. 



They are about the same size as the full-grown apterous females. 



Life History. — The winter is spent by the small females or stem- 

 mothers on the surface of the needles of the red fir or the Douglas 

 spruce. In the spring these females begin to grow and cover the bodies 

 with white, cottony wax and to secrete quantities of honey-dew. About 

 the middle of April or earlier they begin to lay eggs, each depositing 

 from twenty-five to forty. 

 These hatch in about two 

 weeks and the young settle 

 and feed on the new and 

 tender tips of the twigs. 

 They mature into winged 

 and apterous females. The 

 apterous forms deposit eggs 

 which hatch into hibernating 

 females, while the winged 

 forms migrate to the silver 

 spruce and lay eggs which 

 hatch very quickly. The 

 young of these settle on the 

 tender needles at the tips 

 and cause large light-green 

 or purplish galls which may 

 lie from 1| to 2 inches long. 

 About the middle of July 

 those i o the silver spruce be- 

 eonie Eull-grown winged 

 migrants which fly to the red 

 fir or the Douglas spruce and 

 lay eggs which hatch also into 

 hibernating females. Pro- 

 fessor Gillette states that "It 

 is certain that the forms on the 

 Douglas spruce are the de- 

 scendants of the migrants 

 I'n 'in the silver spruce, and it 

 is equally certain that the gall producing forms on the silver spruce 

 are the immediate descendants of the winged migrants from the 

 D< uglas spruce." 



Fig. 5 8. — Cooler's Chermes, Chermes cooleyi 

 Gillette. Young- females covered with white 

 cottony wax on the needles of Douglas spruce. 



Natural size. (Original) 



