SYSTEMATIC TREATMENT 



DEFINITION OF THE GROUP 



The vernacular term "mealy bugs" has been used in the title of this 

 paper chiefly because of a doubt as to the scientific term that should be 

 applied. Whether the group of genera commonly included under this 

 term should be regarded as a tribe, the Pseudococcini, of the subfamily 

 Dactylopiinae, or as a subfamily, the Pseudococcinae, or as a family, the 

 Pseudococcidae, of a super family, the Coccidoidea. is open to debate. 

 Whatever status may be assigned to them it appears quite certain that 

 the genera herein discussed, together with certain others, form a natural 

 group quite distinctly separated from the remainder of the Coccidae, a 

 group that does not include such forms as Dactylopius, Eriococcus, 

 Asterolecanium and other genera of these types with which it is asso- 

 ciated in the Fernald Catalogue. However, this is a question which as 

 far as this paper is concerned is a secondary issue, and I have chosen 

 to employ a vernacular term which is in general quite well understood. 



The group of genera included may be defined by the following char- 

 acters. Coccidae with at least one pair of dorsal ostioles; with entally 

 truncate cylindrical wax ducts; commonly with at least one pair of 

 cerarii; the adult female either with well developed legs or antennae or 

 with these organs vestigial or entirely lacking, commonly more or less 

 covered with cottony or mealy secretion or enclosed within a cottony 

 or felted sac ; without abdominal spiracles ; posterior end of the abdomen 

 neither cleft nor pygidif orm ; never with 8-shaped pores. 



The extent of the group thus defined is somewhat problematical, but 

 from the material available to me for study and from the published de- 

 scriptions it appears that the following genera may be regarded as be- 

 longing here : Antonina, Cryptoripersia, Erium, Geococcus, Lachnodius, 

 Natalensia, Phenacoccus, Pseudococcus, Rhizoecus, Ripersia, Ripersiella, 

 Trabutina, Trionymus and Tylococcus. The genera Cryptococcus and 

 Fonscolombia (at least F. fraxini) are almost certainly Eriococcine al- 

 though their position in the Fernald Catalogue would indicate relation- 

 ship with Pseudococcus. Through the kindness of Mr. E. E. Green I 

 have been enabled to see specimens of both of these genera and in neither 

 Cryptococcus fagi nor Fonscolombia fraxini are the dorsal ostioles pres- 



