206 GYMNOCOCCUS AGAVIUM. 



margin of each. Thorax broad, convex, sides diver- 

 gent to an angle ; posterior angles prominent ; 

 posterior depression large. Wings very long, ample, 

 clear white ; halteres short, white. Terminal fila- 

 ments of the body long, white. Legs long, slender, 

 piceous, with short, projecting, simple hairs ; tibiae 

 very long ; tarsi one fourth as long as the tibia3 ; claws 

 very short. Pupa in a close-fitting sac " (Douglas, 1. c.). 



Long, 1 mm. 



Larva with rudimentary anal lobes as in the adult. 

 Anal orifice with six hairs. Dorsum with six rows of 

 conical spines, not truncate as in Coccus. Antennas 

 (Fig. 6, d) of six joints. 



Habitat (under glass). The following is Mr. 

 Douglas's account of the insect : " In February last 

 I received from Mr. (now Dr.) D. Morris, Assistant 

 Director of the Royal Gardens, Kew, a quantity of 

 white cottony matter that had been collected from the 

 underside of leaves of a species of Agave, which came 

 three years previously from one of the Southern States 

 of North America. This mass contained many of the 

 females of the above-mentioned Coccus, by which it 

 had been produced. They were not attached to it, 

 but on its removal they, by reason of their rotundity, 

 rolled readily about, apparently without life. Having 

 gummed some of them back downwards on to a card, I 

 soon saw that they were not dead, but were in the act 

 of extruding apparently living larvae ; but on observing 

 them more closely with the microscope, under a half- 

 inch objective, I witnessed some long, oval, yellow 

 eggs extruded, from which, while in the very act of 

 parturition, a larva escaped, so that generation is ovo- 

 viviparous; several of the larvae as they appeared 

 clung together. "When all were extruded, the body of 

 the mother collapsed entirely. About a month later I 

 obtained from Kew part of a leaf of the Agave, with 

 the Cocci stationary in situ under the cotton which 

 they had extruded, sometimes three or four under one 

 mass. I also found, mostly on the outside of these 



