1886.] E. T. Atkinson— 0/4 the Homopterous Family Coccida?. 269 



Subfamily Diaspina. 



Diaspides, Sign., A. S. E. F. (4 ser.) ix, p. 98, 1.09 (1869) : Diaspidcv, Maskell, 

 Trans. New Zeal. Inst, xi, 189 (1879) : Diaspince, Comstock, Rep. Dep. Agr. U. S. 

 p. 278 (1880) : Diaspidcje, F. Low, Yerh. zool-bot. Ges. Wion, xxxii, p. 513 (1883). 



The genera falling under this subfamily, as we have seen, are dis- 

 tinguished by a shield or covering formed partly of the cast-off skins 

 of the earlier stages and partly of a filamentary addition thereto secre- 

 ted by the insect itself. Dr. F. Low (1. c.) has recently bestowed some 

 attention on the metamorphoses of this group, and I shall incorporate 

 the result of his investigations in the following account of this sub- 

 family : — 



S . In the adult, the head has four ocelli, two on the underside 

 close to each other and two on the vertex behind the base of each 

 of the antenn83, which are 10- jointed and placed close to each other at 

 the apex of the head, each on a small tubercle : mesonotam in the 

 middle with a transverse band (apodeiiia) which is narrow and of equal 

 breadth throughout, somewhat arched, Yery shining and convex and in 

 most species of a darker colour than the rest of the dorsum. The 

 abdomen is almost as broad as the thorax, broadly rounded at the 

 extremity and furnished there with a knob or protuberance, from 

 which proceeds the genital organ, which is as long as or longer than 

 the abdomen : there are no caudal appendages. Wings oval, the basal 

 lobe but slightly projecting ; the hind- wings are wanting and are 

 replaced by a pair of usually clavate processes, resembling the halteres 

 or poisers of the Biptera, and furnished with a hooked bristle which 

 fitting into a pocket or hollow in the fore-wings steadies them 

 in flight. Legs moderately long ; femora tolerably stout, somewhat 

 flattened and with a notch on the underside near the base ; tarsi with 

 one joint, conical and ending in a simple claw and four knobbed hairs 

 called digitules. The $ rests as larva and pupa under a variously 

 shaped shield which is composed of a single larval skin and of an 

 appendage formed of a stiff (neither filamentous nor felted) secretion, 

 the latter attached to the margin of the former. 



? . Li the adult, the body is circular, pyriform, oval, or longish- 

 elliptical, strongly depressed, without any of the external organs except 

 the rostrum or sucking setiform apparatus. Last abdominal segment 

 (pygidium) very flat, sharp-edged, roundish, semi-circular or obtusely 

 triangular, undivided, furnished on the posterior margin with small lobes, 

 spines, hairs, and scales. There are visible under the microscope by 

 transmitted light on the upper side of this segment a number of 



