270 THE COCCIDAE 



dark in color, blackish or brownish, though in certain species the 

 color is much lighter, varying from light browii to yellow or 

 olivaceous. While in certain species the sides are nearly parallel, 

 in most of the species the sides converge toward one end, the 

 cephalic end, which bears the two exuviae. The exuviae 

 overlap each other. The exuvia of the first nymph bears 

 the remains of the antennae as porrect projections, while the 

 exuvia of the^ /second nymphal female is much larger and fre- 

 quently covers about one-fourth of the outer surface of the scale. 

 The ventral scale is always complete and continuous with the 

 dorsal scale. In certain species the central part of the ventral 

 scale is always thinner, the extent and position of the thinner por- 

 tion is definite for each species and this thinner portion is rup- 

 tured when the scale is removed from the host-plant. In those 

 species where the ventral scale is thicker and tougher, it is not 

 ruptured when the scale is removed. This results in those species 

 with a thin area of the ventral scale as being described as having 

 a divided ventral scale and the others as having the ventral scale 

 entire or complete. Where the ventral scale is very thin and all 

 of it remains attached to the host-plant, it may be described as 

 obsolete or wanting. The wax of the dorsal scale is usually com- 

 paratively thick and tough and not easily broken. 



The scale of the male is elongate, about three times as long 

 as broad with the single exuvia attached at the cephalic end. The 

 sides of the scale are usually nearly parallel and in general the 

 caudal portion is not much wider, as in the second nymphal scale 

 and adult female scale of many species. The male scale is from 

 one-half to one-third the length of that of the adult female. They 

 are quite similar in color and general form to those of the female. 

 There is frequently a thinner transverse band on the caudal part 

 of the scale which serves as a hinge and allows the caudal end to 

 be raised so as to permit of the escape of the adult male. 



The species of this group are quite generally designated as 

 the oyster-shell scales, because of their similarity in shape, color, 

 and general appearance to the shell of an oyster. Unfortunately 

 this resemblance is also found in a few species of Diaspidini, but 

 the name of the oyster-shell scale has been so long applied to the 

 common scale of the apple and to other species of the tribe that 

 there is no hopes now of introducing a different name and it would 

 be unwise to attempt it. 



The body of the adult female is placed at the cephalic end 

 of the scale under the exuviae and the eggs with the pulverulent 



