4 



IIÜMOPTERA 



parts. In earlier stages, mostly flat, in pupating becoming more convex or in some species raised on a 

 beautiful palisade all around of white wax. Pupa case usually with spines or hairs though some of these 

 are often obscure. There is usually more or less of waxy secretion from a marginal rim of wax tubes and 

 often also from dorsum of case, in the shape of rods, or asbestiform, powdery, wooly or flocculent wax, 

 usually of characteristic pattern, and sometimes so copious as to cover the insect. A distinctly Aleyrodid 

 character in the larval and pupal stages is the presence on the dorsum of last abdominal segment of a 

 rounded, ovoid or semielliptical opening, the « vasiform orifice », consisting, as stated for the adult, of 

 the orifice, operculum, and lingula. This is the excretory opening, and from the lingula a sweetish fluid 

 is voided. These structures vary much with difleient species and consequently furnish valuable diagnostic 

 characters. 



Eggs are ellipsoidal, often curved, or flattened on one side, attached firmly to leaf with a short stalk; 

 surface either smooth, or showing minute polygonal markings. 



SYNOPSIS OF GENERA 



Vein of fort lAng i.ith single basal branch ; hind 7i'ino h-Hh single vein. i. Genus Aleyrodes, Latreille. 

 Vein of fore h'ing witli basal and distal branches; hind wing with 



single van 2. Genus Aleurochiton, Tullgren. 



Vein of fore and hind wings each -with basal and distal branches . . 3. Genus Aleurodicus, Douglas. 



I. Genus ALEYRODES, Latreille (O 



Aleyrodes. Latreille (i7g5). 



Type species : A. proletella. Linne = A. chelidonii. Latreille. 

 Subgenera : Asterochiton . Cockerell, type A. aureus. Maskell. 



Dialeurodes. Cockerell, type A. citri. Riley e»i; Howard. 



Trialeurodes. Cockerel!, type A. pergandei. Ouaintance. 



Tetraleurodes. Cockerell. type A. perileuca. Cockerell. 



Characters. — Adults with but a single branch to vein ot fore wing, arising at vèr}-, base, or 

 often apparently distinct. Hind wings with but a smgle vein.. Pupa case without compound pores, and 

 lingula usually not prominently protruding from vasiform vein orifice as in Aleiirodicns. 



Geographical distribution of species. — The genus Aleyrodes is cosmopolitan, and a few 

 species are becoming widely distributed, transported no doubt from one countiy to another on then- 

 food plants, as in the case of species of Coccidce. Conditions are much less favoiable for their dissemina- 

 tion, however, since Aleyrodids infest exclusiveh- the leaves of plants which in most cases are largel}-, 

 if not entirely, removed before shipment. Aleyrodes vaporarwrum , Westwood occurs rather generally over 

 Europe and America, and is recorded from Hawaii ; A . citri, abundant in the Southern United States, 

 occurs also in California, Cuba, Mexico. Brazil, China and possibly Chile. Careful investigation would 

 probably show that some of the species infesting economic plants are much more widely distributed 

 than is at present known to be the case. 



The great majorit}' of species are 3'et known only from the countrj' trom whence described, 

 though in some instances they have evidently been there introduced, their nativity, however, being at 



(i) Greek, altnron, fl.v.- ;. ; m - Iii- name of the genus, originally spelled by Latreille Aleyrodts, was later spelled Aleurvdes, following 

 apparently a note by Burmeist« I! In \ ul. 2. p. b2, ig'i?, « Latreille's Orthographie Aleyrodes muss in Aleuroiies verwandelt werden ». who, 



however, presented no reason fur v.r.- • i. m^^i . jn.l w l.ich seems to have been unwarranted. Also, writers on this genus have not been agreed as to the 

 gender of Aleyrodes and there is consequently lack of uniformity in case ending of specific names. In this list, the original orthography is preserved. 



