16 



SCALE INSECTS. 



by a nipple-like prominence located between the center and the an- 

 terior margin of the scale. The scale of the male is usually darker 

 than of the female, sometimes black, but often gray, the larval scale 

 covering the exuvias very frequently light yellow as with the female. 

 Not uncommonly the circular scale, formed prior to the first molt, is 

 black, while the later additions, giving its oblong shape, are gray. 



E(;g. The egg is never (or rarely ) extruded as such by the fe- 

 male, and as it exists within the body of the mother is a mere amni- 

 otic membrane, and the forming embryo showing through gives it a 

 yellowish-white color. The embryo with the envelope measures 

 about 0.2mm long (ro'oa inch) by 0.1 mm (f^'^jj inch) wide. 



Fic. 5. — San Jost' scale: male adult — greatly en- 

 larged. ( After Howard, Cir. No. 3, 2d ser., 

 Div. Ent., Dept. Agr.) 



Newly Hatched Larva. The young larvae of both sexes are 

 alike, and are pale orange in color with long oval bodies. They 

 measure in length about 0.24inra (,„!•„,-, in.) by 0.1mm (^^\^ in.) in 

 width. The sucking bristles are normally doubled on themselves, 

 but when unfolded are nearly three times the length of the body. 

 The antenna' are apparently five-jointed, the last two joints being 

 much longer than the others, slender, subequal in length, and both 

 finely and distinctly annulated. The last joint bears asmall nipple-like 

 projection near the tip. The head is somewhat concave in front, and 

 the eyes are nearly transparent and slightly purplish. The terminal 

 segment of the abdomen foreshadows in structure the plates and 

 spines of the adult female. The large central plates each terminate 

 in a long hair. The tarsus is represented by apparently a single, 



