Maskell. — On some Aleurodida?. 171 



the form of the orifice just mentioned, and to distinguish the 

 pupse from — say, some kind of Lccaniiiui or Ctenochiton. 



The adult Aleurodidce in most species are very much ahke : 

 the differences — an extra patch or so on the wings, or a shght 

 variation in colour, or some pecuharity in the division of the 

 eyes — are so small that practically the specific distinctions 

 may be best studied in the larvae and pupae. Even these are 

 not always separated by clearly-marked characters recognisable 

 without close examination ; and, on the whole, the family 

 presents many difficulties to the student. 



The bibliography of the Aleurodidce is not extensive at the 

 best ; and, so far as my own studies are concerned, the only 

 modern works available to me are Dr. Signoret's "Mono- 

 graphic sur les Aleurodes," 1867, and a paper by Mr. J. 

 Douglas on a new species (" Entom. Mo. Mag.," May, 1888). 

 Signoret enumerates and summarises some thirty writers, from 

 Eeaumur to Frauenfeld (1867), who have given various notes 

 on the family ; but most of these are either inaccurate or too 

 brief. 



As far as I can ascertain from the authors mentioned, 

 there is only one genus, Aleurodes, of these insects; and to 

 that genus I have attributed the five species described in tliis 

 paper. 



Genus Aleurodes, Latreille. 



Insects with four wings in both sexes in the adult state. 

 Eyes divided ; a single ocellus near each eye. Antennae of 

 seven joints. Wings horizontal, wdiite, floury, often patched 

 with brown ; forewing having only one median longitudinal 

 vein, with a short basal branch. Tarsi of two joints ; claws 

 two, with a third spiny process between them. Abdomen 

 exhibiting a tubercular process, dorsally, on the last segment. 

 Pupae arboreal, stationary, enclosed in a w^axy test which 

 exhibits a subovate orifice near the abdominal extremity. 



Aleurodes sacchari, sp. nov. Plate XIIL, figs. 1-10. 



Adult female insect brown, patched with dark -yellow; 

 antennae and legs yellow. Body rather thick ; length about 

 4^m. ; expanse of wings nearly lin. Forewings white, strongly 

 marked with dark-brown patches ; one patch is at the base of 

 the wing, and two others form clear transverse bands on the 

 surface, leaving the tip of the wmg white ; there are also 

 many smaller scattered spots. Hindwings only very faintly 

 marked with brown spots. Median longitudinal vein of fore- 

 wing strongly marked, angular; basal branch fainter, short. 

 Abdomen having on the last segment, dorsally, a very short 

 process (cornicle) ; extremity sharp, trifid, turned downwards,, 

 bearing a few short hairs at the tip. Antennae of seven 

 joints ; the first two very short, smooth, and thick ; the third 



