66 H. W. Peal — Monograph of the Oriental Aleurodidee. [No. 3, 



Coccids by their possessing four wings to the latter'a two, and from the 

 Pysllids by the venation of the wings. The fore wings of the latter 

 family are supplied with several veins while in the Aleurodidae there 

 are only two (or in some cases three). Tn the larval and pupal stages 

 they can be distinguished from both the Coccidse and Psyllidse by the 

 presence on the dorsal surface of the last segment of the abdomen of 

 a triangular or suhelliptical opening (also present in the adult) known 

 as the vasiform orifice. This orifice has hinged to it anteriorly a plate 

 or flap known as the operculum. This operculum projects and covers 

 to some extent the opening of the vasiform orifice. There is besides in 

 nearly every case a narrow tongue-like organ which lies within the 

 vasiform orifice and which projects caudad more or less into or beyond 

 the vasiform orifice. This is the organ which produces the honey-dew. 



The family is divided into two genera : Aleurodes and Aleurodicus. 

 The species belonging to the genus Aleurodicus have with one exception 

 been all described from the warmer parts of America. 



Genus Aleurodes. 

 Adults with only one branch (basal) from vein of forewing. Hind 

 wing with a single vein. 



Genus Aleurodicus. 

 Adults having the vein in both wings with a distal and basal branch. 



In a recent work by Mr. T. D. A. Cockerell (Proc. Acad. Philadel- 

 phia, May 1902, p. 279), these two genera are divided into several sub- 

 genera. I will deal with these subgenera later on when classifying our 

 Indian species. As regards the bibliography, the principal works dealing 

 with this family are Dr. V. Signoret's papers in the Journal of the 

 Entomological Society of France, 1867 and 1883 ; Mr. W. M. Maskell's 

 papers in the Transactions of the New Zealand Institute 1889, 1890, and 

 1895 ; and Mr. A. L. Quaintance's "Contributions toward a study of 

 the American Aleurodida?," (U.S. Dept. Agri. Technical Series No. 8). 

 From these works the complete bibliography can be obtained. 



Both Mi'. Maskell and Mr. Quaintance have put forward a plea for 

 describing species belonging to the family, not only from the adult 

 insect, but also from the larva and pupa. However objectionable such 

 a practice is in the case of other insects it is perfectly valid in the case 

 of the Aleurodidee. Though in some cases it is true that the perfect 

 insects do differ in some small particulars, such as the occasional pre- 

 sence of spots and bands on the wings, it is practically impossible in 

 most cases to differentiate species from this stage alone. In the larval 

 and pupal stages on the other hand there is a considerable diversity of 



