PAPERS OX BIOLOGY AND AGRICULTURE 75 



Of the true Scale insects, Diaspinae, the best known, 

 is probably the Aspidiotus perniciosus or San Jose Scale, 

 which is only about .06 inch long, and was introduced 

 originally into California (where it got its name), but is 

 now found in most parts of the United States. This 

 Scale is so well-known that a description of it is super- 

 fluous. Kellogg, in "American Insects," says : "Early 

 in the spring, females which have hibernated under their 

 protecting armor begin giving birth to living young, and 

 continue doing this actively for about six weeks, when 

 they die exhausted." 



Aspidiotus ficus, Ashmead, is the Eed Scale of Florida 

 that affects oranges, especially on the trees grown in 

 conservatories. The color is rich reddish brown, almost 

 black, with the central portion much lighter. It is nearly 

 circular in outline, with the molted skins in the center 

 of the scale. 



Aspidiotus aurantii, Maskell, is the name of the Eed 

 Scale of California, which differs from the preceding, as 

 Marlatt** says, "in the fact that the body of the female 

 turns a reddish brown and shows through the thin trans- 

 parent waxy scale. ***** It is controlled by oily 

 washes, and also by the gas treatment. The young are 

 born free, or in other words, the insect is semi-oviparous. 

 and therefore any wash which will kill the old scale will 

 destroy the young also." 



Mytilaspis citricola. Packard, or the Purple Scale, is 

 one of the most plentiful scales affecting both orange ami 

 lemon. It is found in Florida as well as in California. 

 In shape it resembles the Oyster-shell scale of the apple, 

 which is round and flat at one end and gradually narrows 

 to a blunt point at the other. It has a bent or twisted 

 appearance. The color is brownish purple. 



•• C I.. Marlatt. Scale Insects and Mites on Citrus Trees. 



