128 



ECONOMIC ENTOMOLOGY 



halchinjf in June-July, the Forbes Scale (A. Jorbesi John.), and the 

 Curtis Scale (.1. ostrecejormis Curtis) (Fig. 79), are difficult to dis- 

 tinguish from the San Jose Scale, and are also found in orchards. 

 A comparison of the pygidium, or the fused posterior abdominal seg- 

 ments, under the microscope enables one to identify the adults of these 

 species. On the dOrsal surface of the pygidium are the anal opening 

 and the glands that secrete the wax of the scale. On the ventral sur- 

 face are the vaginal opening and 4 or 5 groups of spinnerets (wanting 

 in the San Jose Scale). The margin of the pygidium is modified into 



A B C 



Fig. 80.— Three common orchard scales. A, San Jose scale; B, oyster-shell scale 



C, scurfy scale. 



lobes with thickenings, dorsal and ventral spines, and plates character- 

 istic of each species (Fig. 79). 



Euonymus Scale (Chionaspis eiionymi Comst.) is a common pest of 

 Euonymus in the Eastern United States. Two broods a season. 

 Female scale elongate-oval, brown, with yellow exuvia, convex; male 

 scale white, parallel-sided, 3-ridged, with yellow exuvia, much smaller 

 than female scale. 



Rose Scale {Aulacaspis rasa. Bouche). — Attacks rose, raspberry, 

 blackberry, etc. 



Female scale snow-white, nearly circular, thin and flat, 3^f 2 iiich 

 in diameter; with two light yellow exuviae at margin; oviparous. Male 

 scale shorter, narrower, 3-ridged. Hibernates in all stages, hence 

 all stages may be found on one infested plant. Two or three broods a 



