Maskell. — On Aleurodidae. 437 



Pupa-case yellow, the median region darkening as the 

 pupa approaches its metamorphosis ; form elliptical, with four 

 lateral depressions, two on each side (similar to those in the 

 Goccld genus Lecani urn) ; length about /^in. Dorsum hairless, 

 but bearing, just within the margin, a series of rather large 

 tubercular pustules, subconical with an apical orifice, set 

 somewhat closely together ; and from each of these springs a 

 curling, white, cylindrical waxy tube extending beyond the 

 margin : within this series are twelve other pustules — one, 

 large, on each side of the cephalic region ; one, large, on each 

 side of the thoracic region ; two, large, on each side of the 

 anterior abdominal region ; one, large, on each side close to 

 the posterior extremity ; and one, small, on each side of the 

 vasiform orifice. From these last series of dorsal pustules 

 exudes a thin, yellow, waxy matter, which seems to be very 

 brittle; as it is generally only fragmentary. Margin slightly 

 thickened, composed of slender closely-adjacent tubes ; there 

 is only a very short fragmentary waxy fringe, although, as the 

 dorsal waxy tubes extend beyond the margin, the case seems 

 at first sight to be fringed ; at the posterior extremity there 

 are two setae. Vasiform orifice sub-semi-elliptical, the anterior 

 edge straight ; operculum similar, but about half the size ; 

 lingula exten<ling a little beyond the operculum, the extre- 

 mity clavate, with two grooves. 



Adult form unknown. 



Hab. In Mexico, on Nicotiana tabacum. My specimens 

 were sent by Mr. Cockerell, from Guanajuato. I am not sure 

 whether the occurrence of an insect of the order Homoptera on 

 tobacco is exceptional or not. Some time ago I remember an 

 instance of tobacco in the Customhouse at Wellincjton being 

 found to be infested by a species of weevil which did much 

 damage to the article ; but the living plant, as far as I know, 

 is usually free from pests. 



This species is nearly allied to A. erigerontis {ante), but 

 diffei's in the vasiform orifice, in the arrangement of the dorsal 

 pustules, and in the lateral depressions. 



41. Aleurodes niger, Maskell, sp. nov. Plate XXXIII. — 1. 



Larva not observed. 



Pupa-case at first flatfish, but later very convex ; form 

 regularly elliptical ; length about -^g™- > colour very dense 

 dull -black. Dorsum minutely striated ; abdominal segments 

 fairly distinct ; there are no dorsal hairs or spines. Margins 

 very indistinctly crenulated, the crenulations very wide and 

 shallow ; there is no fringe. Vasiform orifice small, serai- 

 elliptical ; operculum covering about half the orifice ; lingula 

 not observed with certainty, probably obsolete. 



Adult form unknown. 



