20 MORPHOLOGY AND TAXONOMY OF ADULT MALES 



subepisternal ridge (ser) articulates dorsally with the triangular plate and extends 

 obliquely to approach the marginal ridge of the basisternum, thus bounding the 

 mesepisternum (eps2) anteriorly. The mesepisternum is divided into a larger 

 dorsal part, the supraepisternum or anepisternum, and the small ventral part, the 

 infraepisternum or katepisternum (Snodgrass, 1935), both of which are separated 

 by a membranous area. The katepisternum anteriorly fuses with the later opleurite 

 (lpl) which is attached to the lateral arms of the marginal ridge of the basisternum ; 

 the lateropleurite is narrow (e.g. Planococcus group), but comparatively wide (e.g. 

 Nairobia group). A small and well sclerotized mesepimeron (epm2) is present 

 immediately behind the pleural ridge, just above its articulation with the coxa. 

 A slender sclerite, presumably representing the trochantin (tn) occurs just anterior 

 to the coxal articulation, and was found in all the species studied except N. bifrons. 

 This sclerite was first described and illustrated by Giliomee (1961). 



The mesothoracic spiracle (sp2) with its atrium and its supporting bar, the peri- 

 treme, is placed latero-ventrally anterior to the subepisternal ridge. 



The mesosternum is represented by a large, slightly convex and hexagonal plate, 

 the basisternum (stn2) ; this plate is framed antero-laterally and latero-posteriorly 

 by the marginal and the precoxal ridges (mr & pcr2), respectively. In Saccharicoccus 

 group the median part of the marginal ridge is completely absent (Text-figs. 27-30). 

 The precoxal ridge posteriorly fades away before reaching the median line, where 

 the posterior margin of the basisternum becomes slightly inflected to form a furcal 

 pit (fp) from which the strong, two-armed furca (f) originates. The longitudinal 

 median ridge of the basisternum, which occurs in many species of Margarodidae, 

 Diaspididae and Coccidae (Theron, 1958 ; Ghauri, 1962 and Giliomee, 1967), is 

 absent in Pseudococcidae (and Eriococcidae). 



The wing articulation : The articular system of the fore wings is apparently the 

 same in all the coccids, and only slight differences are shown in the size of the alar 

 sclerites, the pter alia, which include : the tegula (teg), the axillary (first, second and 

 third) (axi, ax2 and ax3) and the additional sclerites (asc). The costal complex of 

 veins (ccx) and the axillary cord (axe) give support to the anterior and posterior 

 margins of the wings at their bases. Apart from these structures, the articulation 

 also involves the anterior notal wing process, the pleural wing process, the basalare 

 and probably the subalare. 



The dermal structures of the mesothorax : The fleshy setae occur in the Pseudo- 

 coccus group only, in the postmesostigmatal area, but the hair-like setae are always 

 present, arranged in the following topographical groups : the prescutal setae (pscse) 

 the scutal setae (sctse) ; the scutellar setae (scls) ; the tegular setae (tegs) ; the 

 postmesostigmatal setae (pms) ; the basisternal setae (stn2s). The postmesostigmatal 

 setae may be absent (Nairobia group) or present only laterally behind the meso- 

 thoracic spiracles (e.g. P. kenyae, Text-fig. 3), or also in the median and the sub- 

 median areas in a transverse band (e.g. P. citriculus, Text-fig. 23). 



The numbers of the mesothoracic setae vary in the different species and con- 

 stitute useful key characters. 



With the exception of Nairobia group, the mesothorax usually carries a number 



