98 MISS EMBLETON ON CEEATAPHIS LATAISTI^. 



"wax is secreted. The eyes are still conspicuous as dark red-brown 

 spots. The body, still powdered over with a fine white dust 

 which soon disappears, is broader than in the preceding stage 

 and is less flattened. The antennae and legs are unchanged ; the 

 head is less pointed, and the rostrum ends between the second 

 and third legs. 



As the adult condition is approached the activity becomes less, 

 while the colour deepens and the body becomes more round in 

 outline and more arched dorsally The adult insect (PI. 12. fig. 2), 

 like a Coccid, is fixed by the suctorial proboscis to the host plant, 

 and appears as a dark, almost black, rounded excrescence, 

 surrounded by a conspicuous fringe of white wax ; it is about 

 1*50 mm. in length and 1'25 mm. in width : the antennae are about 

 '23 mm. in length, but are usually hidden by the border of wax. 

 Across the dorsal surface, about halfway back, is a deep furrow, 

 caused by the articulation becoming more marked in these two 

 segments, separating the thorax from the abdomen, and so the 

 insect has the appearance of being, to some extent, divided 

 across the middle. Dorsally, in the posterior region of the 

 body, are two cornicles as shown in figs. 7-9. The eyes are now 

 inconspicuous. 



The confusion that has grown up in the literature relating to 

 this insect has been due, as I have already stated, to the fact 

 that it closely resembles many Coccidce and Aleurodidce. The 

 three great families of these insects — Coccidce, Aleurodidce, 

 Aphidce — have, so far as outward appearance goes, much in 

 common, and systematically the members of these families are 

 distinguished from one another by such minor points as differ- 

 ences in the number of joints in the feet and antennae. But the 

 real distinctions are biological, occurring in the life-histories — 

 the Coccidce going through a complex metamorphosis which is 

 totally diff'erent in the two sexes, resulting in the production of 

 imagoes where the two sexes differ completely. The Aleurodidce, 

 though they show a remarkable series of metamorphoses, are 

 identical in the two sexes, and these are constantly produced in 

 each generation, the development resulting in the production of 

 the normal Hemipterous form, alike for male and female. 

 The Aphidce, on the other hand, exhibit a very different and 

 striking series of changes, the unique feature of which is that the 

 development is, so to speak, spread over a number of successive 



