INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



113 



DACTYLOPIIN^ (Subfamily) 



The members of this subfamily are much more varied than those of 

 the two preceding. In some species the power of locomotion is retained 

 throughout the entire life cycle, while in others the legs disappear after 

 the first moult and the insects soon become fixed in position. The 

 bodies are entirely unprotected except by the secretion of a white cot- 

 tony powder or wax. The eggs may be enclosed in the secretion cover- 

 ing the females, or they may be deposited in cottony masses. Among 

 the members are the mealy bugs, which are very troublesome in this 

 State. 



THE PIT-MAKING OAK SCALE 

 Asterolecanium variolosnm Ratzeburg 



(Fig. 91) 



Description. — The scales are 

 appearing semi-transparent and 

 pretty species, which is 

 not often met with. 



Distribution.— 

 Though rather common 

 in the Eastern States, 

 it has been reported on 

 a single oak tree on the 

 high school grounds at 

 Stockton, by "Wm. Gar- 

 den, and quite plentiful 

 at Stanford University, 

 by Professor R. W. 

 Doane. 



Food Plants. — Vari- 

 ous species of oaks are 

 attacked, including 

 Quercus sessiliflora, Q. 

 glandulifera, holly oak 

 (Q. ilex) and Q. aurea. 

 It sometimes kills the 

 small twigs. 



Control. — Control 

 measures are the same 

 as for soft brown scale 

 or the European fruit 

 Lecanium. 



circular, shiny green or yellow, 

 T V inch in diameter. It is a very 



Fig. 91. — The pit-making oak scale, Asterolecanium 

 variolosum Ratz. The twig on the right shows the 

 pits made by the scale. Enlarged three times. (Orig- 

 inal) 



THE OAK CEROCOCCUS 71 



Gerococcus quercus Comstock 

 (Fig. 92) 



Description.— The female scales are enclosed in a smooth or rough 

 mass of rich yellow wax, well illustrated by Fig. 92. The individual 



"Ehrhorn's Cerococcus (Cerococcus ehrhomi Ckll.) is common in the central part 

 of the State on oak trees. It is a very small insect and is usually hidden under the 

 scales of the bark and not at all conspicuous as the oak Cerococcus. 

 8 — 13664 



