270 E. T. Atkinson — On the Homopterous Family Coccidse. [No. 3, 



organs in the form of circular openings {'pores) or tubes, whicli are 

 either collected in groups or stand in irregular rows along the margins, 

 and which are probably organs of secretion, hence the name spinnerets 

 (JiUeres). These organs afford specific and generic characters of value. 

 The female individuals lie either in all stages free beneath a variously 

 formed shield, which is made up of two larva-skins each with an ap- 

 pendage of stiff secretion at its margin, or they are enclosed as mature 

 females in the second of the skins included in the shield, and then only 

 the first skin possesses a secretional appendage. We shall now further 

 examine the shield. 



This shield varies much in shape and colour according to genus 

 and species. As observed before, it is composed of the cast-off skin 

 and a secretion formed by the insect itself. In the 5 there are two 

 of these cast-off skins present in the shield a^nd in the ^ but one. In 

 both sexes the larvae possess six legs, antennae, and a rostrum, and are 

 not distinguishable from each other. They attach themselves to the 

 food-plant on which they live by the rostrum or sucking apparatus, and 

 the abdomen soon begins to grow, the extremities, however, remaining 

 of their original size. In this stage there is no shield, but, after the 

 lapse of a few days, the first moult takes place, and the cast-off skin 

 preserves the characters of the change that then takes place. From an 

 examination of this skin it appears that, contrary to the process obtaining 

 in the Gicadce and other families of the Homoptera, in the first shedding 

 of the skin the dorsal portion is entire, and it is the lower side of the 

 front portion of the abdomen that bursts and allows exit to the insect. 

 The skin of the dorsum is compact or felted and semi-corneous, whilst 

 that of the sternum and foreparts of the abdomen is comparatively soft 

 and delicate ; and these characters are preserved in the exuviae, which 

 show the dorsal portion entire and the sternal portion burst open and 

 often unevenly torn in the process. The larva then commences to 

 deposit a secretion on the edge of this skin so as to gradually form 

 an appendage varying in shape and colour accoiding to the genera and 

 species, and which together with the exuviae form the shield under which 

 the larva lives. Up to this point in their history there is no difference 

 in the development of the sexes, but here they diverge. 



$. According to Dr. Low, when the shield has been formed as 

 above described, a second moult takes place and this time the dorsal sur- 

 face bursts and the very delicate cast skin is not incorporated with the 

 shield but is extruded posteriorly : the shield remaining the same. The 

 appendage to the first larval skin formed by the added secretion varies 

 in the different genera ; in Aspidiotus and Aonidia this secretion surrounds 

 the larval skin as a more or less broad, circular, oval or elongate-oval 



