CLASSIFICATION OF THE ALEYRODID.€-PART II. 



INTRODUCTION. 



The present paper deals with the subfamily Aleyrodinae and, with 

 Part I, completes the classification of the family. It has not been 

 feasible to treat at tliis time the species of this subfamily in the manner 

 followed in Part I. Monographic reports of the respective genera of 

 the Aleyrodinas arc, however, now under way and will be issued as 

 rapidly as practicable. 



Students of the Aleyrodidse are well aware that the original and 

 typical genus Aleyrodes had come to include a rather heterogeneous 

 assemblage of forms. This fact was indicated some years ago by 

 Prof. T. D. A. Cockerell in liis paper, "Classification of the Aley- 

 rodida?," ^ in wliich several subgenera were proposed, as Dialeurodes, 

 Tetraleurodes, etc. From the wiiters' studies of these insects it 

 appears to them that Aleyrodes Latreille should be restricted to 

 those species essentially Hke 'proletella L., the type species, and that 

 other genera should be erected to include the remaining forms. This 

 they have attempted to do, as set forth in the following pages. 



Unfortunately the Aleyrodidse are as yet largely known only from 

 the pupal stage, a condition due to their mode of life. A comprehen- 

 sive classification based on the study of the adults would not, there- 

 fore, be possible for many years to come. In the generic diagnoses 

 given herewith it has been necessary to place importance on the char- 

 acters of the so-called pupa case, as has long been the practice in 

 describing species of tliis family. In the majority of the genera pro- 

 posed the adult stage of one or more species, however, is known, and 

 so far as data at hand indicate, adult characters confirm the grouping 

 of species followed, as based on the characters of the pupa case. 



The writers regret that there should be so many species (14 in num- 

 ber) wliich they are unable to assign satisfactorily to any genus by 

 reason of inadequate descriptions, or failure of authors to describe in 

 sufficient detail those characters of most value in generic determina- 

 tions. It is much to be desired that descriptions of Ale}Todid8e be 

 made as complete and full as possible. 



It should be added that careful examinations have been made of 

 the types or cotypes of species described by Maskell, Bemis, Quain- 

 tance, Britton, Morrill, Back, Kuwana, and Kotinsky, and of most of 

 those described by Cockerell. 



> Proc. Acad. Nat. Sci., Phila., p. 279 (1902). 



95 



