OF THE FAMILY COCCIDAE 17 



reticulation were not described by Theron (1958). The deep cervical groove 

 immediately behind the genae indicates the posterior margin of the head. 



Ventromedially, immediately behind the ocular sclerite, the preoral ridge (pror) 

 is situated. It has the form of an inverted V and is very narrow. It fuses 

 posteriorly with the postocular ridge. Sometimes it is completely absent (the 

 ERIOPELl IS group, Genus A ; Text-figs. 24, 26, 27 and 20 ; C). 



The preoral ridge gives support to the cranial apophysis (ca), which is a strong 

 scoop-like structure (Text-figs. 24, 39 ; T). Its apex is usually bifurcate, but 

 sometimes trifurcate (Eriopeltis sp., Text-fig. 24, C) or truncate (E. pela, E. Pfestucae, 

 L. luzulae ; Text-figs. 18, 26, 27 ; C). In some cases the apex also carries an 

 irregular central lobe, which is very pronounced in Genus A (Text-fig. 20, C). 

 Theron (1958) found that in P. pomeranicum eight antennal muscles are attached to 

 the apex of the cranial apophysis. The length of the cranial apophysis varies 

 within the family. It is long in some species (e.g. C. hesperidum, Genus B ; Text- 

 figs. 31, 33 ; C), reaching the level of the anterior margin of the ventral eyes, while 

 in others (e.g. E. tiliae, P. piceae and /:. pela ; Text-figs. 2, 6, 18) it does not extend 

 beyond the posterior level of these eyes. 



An irregular mouth opening (mo) is situated on a slight membranous bulge behind 

 the cranial apophysis. On each side of the mouth opening, immediately median to 

 the junction of the preoral and postocular ridges, a tendon-like apodeme (t) is present. 

 According to Theron (1958) it serves for the attachment of a muscle which extends 

 to the posterior margin of the median crest. In R. spiraeae this apodeme has a 

 broad base and in Genus A it arises from the anterior part of an elongated sclerite 

 (Text-fig. 20, vs) which appears to represent the ventral sclerite described by Theron 

 (1958) in the margaroid Pseiidaspidoproctits PfuUeri. The ventral sclerites were 

 regarded by Theron as vestiges of the ventral plate found in Margarodes. They 

 are also present in some Diaspididae (Ghauri, 1962). 



The tentorial pits are situated in the membrane around the mouth opening. In a 

 few species (e.g. the ERIOPELTIS group ; Text-figs. 24, 26, 27 ; C) four tentorial 

 pits are present. The two anterior ones (atp) are situated anterolateral to the 

 mouth opening, near the preoral ridge when the latter is present ; these pits are, 

 however, usually absent. The posterior tentorial pits (ptp) are found posterolateral 

 to the mouth opening, immediately median to the posterior ends of the postocular 

 ridges ; they are always present. From each posterior pit a thread-like posterior 

 tentorial arm (Text-figs. 24, 39 ; T ; pta) extends towards the heavily sclerotized 

 tentorial bridge (Text-figs. 24, 29, T ; tb). From the bridge the somewhat stouter 

 anterior tentorial arms (Text-figs. 24, 39 ; T ; ata) extend towards the cranial 

 apophysis. It is difficult to make out exactly how these arms are associated with 

 the cranial apophysis. When the anterior tentorial pits are present, a thread-like 

 anterior extension from each tentorial arm, possibly representing the dorsal tentorial 

 arm links the anterior arms with the edges of the cranial apophysis (Text-fig. 24, T). 

 When the anterior pits are absent, the arms are intimately associated with the 

 cranial apophysis, as shown in Text-fig. 39, T. The latter condition appears to be 

 the result of a process in which the anterior pits have drifted forwards until they 



