OF THE FAMILY COCCIDAK 21 



The Thorax 

 Prothorax 



The prothorax is largely membranous, with only a few sclerites and ridge-like 

 structures present. It is distinctly separated from the head by a deep cervical 

 constriction. In this respect the Coccidae resemble the Pseudococcidae (Theron, 

 1958 ; Giliomee, 1961). 



Dorsally, immediately behind the neck region, the collar-like pronotal ridge (prnr) 

 runs continuously from one side to the other, extending ventrally and closely approxi- 

 mating the proepisternum + cervical sclerite. It is usually interrupted by weak 

 sclerotization dorsomedially, but in E. pela the ridge is apparently uninterrupted, 

 although very narrow medially. This structure has been called the " protergal 

 sclerite " (Habib, 1956), the " prothoracic suture " (Ezzat, 1956) and the " pro- 

 thoracic arch " (Borchsenius, 1957). Dorsolaterally, behind the pronotal ridge, a 

 small sclerite is closely associated with it ; this sclerite appears to be homologous 

 with the lateral pronotal sclerite (prn) described by Giliomee (1961) in the Pseudo- 

 coccidae and Ghauri (1962) in the Diaspididae. The sclerite was called the 

 " prothoracic sclerotized plate " by Borchsenius (1957). Theron (1958) did not 

 mention them. 



In the posterolateral part of the prothorax a small sclerite is situated ; it con- 

 stitutes the so-called post-tergite (pt). It sometimes shows irregular wavy striations 

 (e.g. most species of the COCCUS group). In Eriopeltis sp. the sclerite is apparently 

 absent and only represented by striations of the derm. The post-tergites have not 

 been observed in this family before. 



In the pleural region the pleurites and neck sclerites are reduced to a single ridge- 

 like structure, called the proepisternum + cervical sclerite (pepcv) (Ghauri, 1962). 

 Anteriorly it passes just below the ventral end of the pronotal ridge and appears to 

 be joined by weak sclerotization to the postocular ridge. For a short distance 

 behind the level of the pronotal ridge this sclerite is less strongly sclerotized. This 

 phenomenon was also observed in Pseudococcus (Giliomee, 1961). Posteriorly the 

 sclerite is delimited by a short pleural ridge (plr^, which articulates ventrally with 

 the basal process of the coxa ; dorsally it is invaginated to form a small pleural 

 apophysis (pla x ). Crampton (1926) called the structure a " neck plate " or 

 " laterocervicale " in Coccus. He also distinguished an episternum and epimeron, 

 but no structure corresponding to the latter was observed in the species studied 

 here. From his illustration (fig. 55) it appears that he misinterpreted the position 

 of the pleural ridge. The proepisternum + cervical sclerite has also been referred 

 to as the " pleural sclerite of the prothorax " (Ezzat, 1956), the " propleural sclerite " 

 (Habib, 1956) and the " sclerotized plate of the anterior leg " (Borchsenius, 1957). 



The prosternum (stnj is represented by a single sclerite, of which the degree of 

 development shows considerable interspecific and also some intraspecific variation. 

 In its most complete form it consists of a triangular, sometimes oval sclerite, which is 

 bounded posteriorly by a strong transverse ridge and traversed by a longitudinal 

 median ridge. Sometimes the prosternal sclerite is more or less reduced (C. 

 hesperidum, Text-fig. 31), while the median ridge may be complete (e.g. P. myrtilli, 



