22 MORPHOLOGY AND TAXONOMY OF ADULT MALES 



C. hesperidum ; Text-figs. 12, 31), interrupted in the middle (e.g. E. tiliae, E. 

 Pfestucae, P. corni ; Text-figs. 2, 26, 38), developed anteriorly only (e.g. Eriopeltis 

 sp., P. pomeranicum ; Text-figs. 24, 39), or represented by a basal stalk (R. spiraeae, 

 L. luzulae ; Text-figs. 8, 27). In some species the degree of reduction of the median 

 ridge varies individually, e.g. in F. viburni and P. Pbetulae the ridge may be complete 

 or developed anteriorly only, while in P. bituberculatum and S. prunastri it may be 

 absent or represented by a short basal stalk only. On each side of the transverse 

 ridge a shallow depression probably represents the sternal apophysis. Its position 

 corresponds to that of the sternal apophyses in the more primitive Phenacolea- 

 chiidae (Theron, 1962). In some individuals of most species a small apopysis is 

 situated medially anterior to the presternum. It probably serves for the attachment 

 of muscles, as four muscles originate in the corresponding area in the Pseudococcidae 

 (Makel, 1942). Theron (1962) describes a " mammillate organ " from the same 

 region in the Phenacoleachiidae, saying that it is probably homologous with the so- 

 called salivary gland of Pseudaspidoproctus. The derm of the prosternum is occasion- 

 ally polygonally reticulated (C. hesperidum, Text-fig. 31) or covered with numerous 

 small spines (/. theobromae, Text-fig. 29). The prosternum was overlooked by most 

 earlier workers. Crampton (1926) figures a linear basisternum and sternellum, 

 while Ezzat (1956) called this region a basisternum ; Borchsenius (1957) regarded 

 it as part of the mesosternum. 



Dermal Structures. Both fleshy and hair-like setae are present in various regions 

 of the prothorax. They occur in the following groups : 



(i) Lateral pronotal setae (lpns), which occur on or immediately posterior to the 

 lateral pronotal sclerites on each side, and may consist of up to 3 fleshy or hair-like 

 setae. They are of very little taxonomic significance as they are only present in 

 some individuals of certain species (e.g. P. pomeranicum, Text-fig. 39). 



(ii) Medial pronotal setae (mpns), which are situated between the pronotal ridge 

 and the post-tergites and usually consist of two widely separated hair-like setae 

 (e.g. P. myrtilli, S. prunastri, C. hesperidum, Text-figs. 12, 22, 31) ; in P. bituber- 

 culatum (Text-fig. 10) the two setae are situated close together on the median line. 

 In other species (e.g. N. abietis, I. theobromae) one or both setae may be absent, 

 while medial pronotal setae are absent altogether in some species (e.g. E. tiliae, 

 L. luzulae). One or two fleshy setae are occasionally associated with these setae. 

 Medial pronotal setae are also found in the Pseudococcidae (Giliomee, 1961). 



(iii) Post-tergital setae (pts) occurring on, or behind and below the post-tergites. 

 They consist of fleshy setae only (up to 13) and were found in the closely related 

 genera Pulvinaria, Coccus and Genus B (Text-figs. 31, 33, 35, 37), but not in the 

 other species. 



(iv) Anteprosternal setae (astnjs) consisting of a number of fleshy setae (up to 7) 

 which occur immediately ventral to the anterior part of the prosternum 4- cervical 

 sclerite (pepcv). They are present in the COCCUS group (Text-figs. 31-43) and 

 sometimes in L. luzulae. 



(v) Prosternal setae (stn^), which are found on and around the prosternum, 

 anterior to the level of the transverse ridge ; in the COCCUS group they extend 



