1886.] E. T. Atkinson— 0?i the Homopterous Family Coccidae. 271 



border, which is more or less convex according to the shape of the larva 

 within it. It is attached too to the larval skin inf such a way as to 

 place the skin somewhat away from the middle towards the side of the 

 shield. In the other genera, the larval skin lies at the base of the 

 shield, whilst the attached secretion forms a straight caudal appendage, 

 which is not so broad as, or but a little broader than, the larval skin itself. 

 In Diaspis and Ohionaspis, this appendage is:parallel-sided, flat, with the 

 sides and the middle longitudinally ridged, whilst in others it is convex, 

 fluted, highest next the hinder end of the [larval skin, and posteriorly 

 generally somewhat flattened, with the sides parallel or a little dilated. 

 The next change produces the adult $ already described. 



? . When the larva, after casting the first skin as already explained 

 and after adding to it a secretion to form a shield, has attained to a 

 certain age, it undergoes a second moult beneath the shield and be- 

 comes a fully developed female. The process undergone indicates two 

 separate groups, which may be thus distinguished : — 



(a). Asjpidiotaria : — in the genera Asipidiotus, Bias^is, Targionia^ 

 Parlatoria, CJiio7iaspis, and Mytilaspis, the ? completes the second moult 

 exactly like the first, bursting through the skin on the underside, and 

 the second skin, like the first, is shield-shaped, compact, felted, and entire, 

 and becomes attached to the inner side of the first skin so as to form a 

 part of the shield, under which the insect moves freely about. The 

 perfect ? then completes the shield by adding to it an appendage formed 

 of the same secretion as that produced by the ^ . 



(6.) Leucaspiaria : — in the second group, formed of the genera 

 Leucaspis, Aonidia, and Fiorinia, the second moult does not take place 

 by the bursting of the skin, but the body shrivels up towards the 

 head and thus becomes detached from the skin. The insect remains 

 enclosed in t'le skin as in a cocoon, and the skin retains the shape and 

 size of the larva from which it has been shed and is as large, or nearly 

 so, as the shield which was already formed when this second moult 

 took place, and adheres rather firmly to it. Above, it is compact and 

 felted, below soft and thin, and completely envelopes the female, which 

 ceases to grow and is, in fact, smaller than in the preceding larval 

 stage. Therefore, in species belonging to this sub-family, the ? can be 

 at once recognised by the presence of two cast-off skins in the shield, 

 the first of the first moult with an appendage formed by the secretion 

 referred to, and which varies in form with the genus, and, below it and 

 to a certain extent behind it, the larger cast-off skin of the second 

 moult, covered partly by the first skin and partly by its appendage. 

 In those cases in which the adult $ is free, this second larval skin has 

 a further secretion of its own, but in the second group, where the ? 

 35 



