1902.] NATURAL SCIENCES OF PHILADELPHIA. 279 



THE CLASSIFICATION OF THE ALEYRODIDil. 



BY T. D. A. COCKERELL. 



The Americau species of this homopterous family have been 

 well treated by Quaiutauce (Tech. Bull., 8, Div. Ent., Dep. 

 Agric, 1900); in the following essay au attempt is made to 

 classify and catalogue the species of the world. 



ALEYRODIDJE Westwood, 1840. 



Adults of both sexes with two pairs of wings, which are rounded 

 apically and appear more or less mealy ; the edges of the wings are 

 ornamented with a distinct sculpture or little bunches of bristles. 

 Autennse simple in form, seven -jointed ; first two joints short and 

 stout. Legs six, all well developed. Eyes often constricted in the 

 middle, or even completely divided. Tarsi with two claws. Size 

 always small. 



Egg elliptical, with a short peduncle (fig. 9). 



Larva oval, with short, stout legs. 



Pupa quiescent, oval, often with a waxy fringe. INIargiu vari- 

 ously scidptured (figs. 4, 5, 6). Abdomen sometimes with large 

 secretory pores (fig. 4). On the dorsal surface of the abdomen is 

 an orifice, known as the vasiform orifice, provided with a more or 

 less rounded flap, the operculum, and a usually elongate narrow 

 two-jointed structure, the lingua (fig. 3). 

 Adult with the median vein of wings forked ; pupa with the lingua 



large, Aleurodkts. 



Adult with the median vein of wings not forked ; pupa with the 



lingua usually small, Aleyrodes. 



ALEURODICTJS Doufrlas. 

 Aleurodicua Douglas, Ent. Mo. Mag., Ser. II, Vol. 3 (1892), p. 33. 

 All the species belong to the warmer parts of America, except A. 

 hohnesii from Fiji, which was, I suspect, introduced fi'om America 

 with the Pddium on which it feeds. The adults are easily recog- 

 nized by the venation of the wings (fig. 1), although Aleyrodes 



