578 



STATE BOARD OF AGRICULTURE. 



The difficulty with which this species is detected is one of its worst 

 features. The scales are so very inconspicuous that it is extremely diffi- 

 cult to find thein before they have become so numerous that severe meas- 

 ures are required to check their increase and spread. 



The appearance of this scale when in large numbers is that of a black 1 

 ish grey scurfy deposit over the whole or any part of a tree (Fig. 7). 

 When more closely examined, this covering is seen to be made up of 

 myriads of small papery scales which can easily be detached by the 

 thumb-nail, thus exposing the yellow or orange-colored bodies of the 

 insects under them. These easilv crush into an oilv mass. The bark 

 under and immediately around the scales is often stained wine-color, 

 probably by some secretion or deposit of the insect. This, however, must 

 not be taken as proof positive of the identity of the scale, for other scales 

 closely resembling the one in question may produce the same effect. 

 The individual scales are of two types, the scale of the female being 

 several times larger than that of the male. The scale of the female 

 (Fig. 8, 7) is nearly circular and flat, with the exuvia? or cast skins 



'9- 



Fig. 8. San Jose Scale (Aspidiotuspemiciosus). 



Fig. 9. Eccentric Scale {Aspidiotus ancylus) 



of the larva in the center. It is grey in color, while that of the exuviae 

 varies from yellow to reddish-yellow or else is black. It measures one to 

 two mm. (.04 to .08 inch). The scale of the male, on the other hand, is 

 darker, usually almost black, and elongated (Fig. 8, 2). The cast skin is 

 usually black and appears as a tiny nipple-like prominence. The male 

 scale is about half as long as the diameter of the female scale. 



These insects pass (he winter in a partially-grown condition. A( this 

 time, before they become weatherbeaten and eroded, the scale shows a 

 small central nipple surrounded by the slightly raised margin of the 

 second larval skin, forming a minute elevated mound surrounded by a 

 tiny ridge, the whole elevated and surrounded by the remainder of the 

 scale, which varies in size according to the degree of maturity that it 

 lias attained. 



As they are very small and dark in color at this time, the scales are 

 naturally difficult to locate. This is readily understood if we remember 

 that when a tree tirst becomes invaded there will be very few insects 

 present, these only about the size of a small fly-speck and very likely 

 placed under the base of a leaf. Onlv after they have become more or less 



