CHAPTER II. 

 DIASPIN^E Continued. 



PURPLE SCALE. 



(Mytilaspis citricola, Packard.) 

 [Plate III, Fig. 1, la, 1&, lc.] 



Scale of Female. The scale of this species is larger than that of the 

 Long Scale. Large females exceed 3 mm (-$ inch) in length. The form 

 is broadly trumpet-shaped, increasing in width behind, sometimes 

 curved, like a cornucopia, but never with the sides parallel. The sur- 

 face is smooth and even glossy, and the color varies with age from light 

 to dark red-brown and purple. The molted larva skins are very plainly 

 indicated; they are browned by the sun so as to appear scorched. 



Scale of Male. The scale of the male is less than half as long as that 

 of the female (1.4 mm = yj^ inch); it is also more linear in shape, and 

 uniformly dark purple in color. The thin hinge is always indicated by 

 a line of lighter color across the upper surface of the scale, near the 

 outer end. 



The purple color of the male scales gives the mass of scales in the 

 aggregate a characteristic hue, which readily distinguishes this species 

 from all others found upon the Orange. 



Female. The insect within, as well as its outer covering, has a 

 broader and less linear form than the Long Scale. The two species 

 also differ in the number and structure of the microscopic plates and 

 spines, with which the margins of the last two joints of the body are 

 armed. The number of excreting pores and spinnerets is greater in M. 

 citricola than in M. gloverii. 



Mature females of the Purple Scale are 1.3 mm (y^ inch) in length, 

 and occupy less than half the space within their completed scales. The 

 color is white, tinged with yellow at the extremities. 



Male. The male and also its pupa are pale amethyst in color. The 

 perfect insect is about l mm ( T ^ inch) in length, and, excepting in ite 

 somewhat stouter- form, hardly differs from the male of the preceding 

 species. 



Egg. The eggs are pearly white, never amethystine, 0.2 mm (yA^ inch) 

 long, elongate oval, often somewhat distorted in shape by crowding. 

 They are laid usually in four rows, but the eggs at the outer end are 

 26 



