i 4 MORPHOLOGY AND TAXONOMY OF ADULT MALES 



the preocular ridge is present but above the ocellus, thus it is not strictly homologous 

 with the interocular ridge ; nevertheless, it probably serves the same purpose and 

 may represent another independent morphological means to the same functional end. 



The ocular sclerites (ocs) are weakly sclerotized plates on each side of the head ; 

 rather large in Ceropnto and Nairobia groups (where the ocular ridges are separated), 

 but are comparatively smaller and traversed on each side by the interocular ridge, 

 in the remaining groups. 



The preoral ridge (pror) is extremely slender and latero-posteriorly connected to 

 both the postocular ridge and to the proepisternum + cervical sclerite, by means 

 of a small triangular and weakly sclerotized plate. 



Two pairs of simple eyes (accessory eyes, Berlese, 1893 ; ocelli, Green, 1922) 

 surrounded by a narrow area of polygonal reticulation, and one pair of transparent 

 lateral ocelli (o) (primary eyes, Krecker, 1909 ; rudimentary eyes, Green, 1922) are 

 present in the species studied. Beardsley (1962) recorded 7 pairs of simple eyes 

 and a pair of ocelli in one species, Puto yuccae, and the complete absence of the 

 ocelli in another, Rhizoecus falcifer. The widely separated dorsal eyes (dse) are 

 borne on the dorsal part of the ocular sclerites, between pre- and postocular ridges. 

 The ventral eyes (vse) are much approximated and placed on the ventral protrusion 

 of the head ; these, although usually somewhat larger than the dorsal eyes, are 

 sometimes smaller (N. vastator), or both subequal (e.g. C. pilosellae). The ocelli 

 are usually large and well developed ; in the Planococcus, Pseudococcus, Sacchari- 

 coccus and Octococcus groups the ocelli are situated at the base of the fork of the 

 Y-shaped complex of ocular ridges, and are dorsally supported by a slender ocellar 

 ridge (see lateral views) ; in Ceroputo group, where the Y-shaped complex is absent, 

 they are supported by the postocular ridge and either a rudimentary sclerotized 

 projection (Text-fig. 34), or a ridge-like arm (Text-fig. 36). In Nairobia group, the 

 ocelli are vestigial and merely represented by atrophied spots. 



The genae (g) are membranous, laterally bulging behind the postocular ridges and 

 without any reticulation ; they form the latero-posterior margins of the head. 



The ventral cavity (vc) is a longitudinal, narrow, slit-like invagination in the 

 median line of the head. From the roof of this invagination arises the internal 

 cranial apophysis (ca) which is always apically truncate ; according to Theron 

 (1958), the cranial apophysis serves for the attachment of the antennal muscles. 



The non-functional month opening (mo) is small, situated behind the preoral 

 ridge. The " tendon-like apodeme " described in other families (Theron, I.e.) is 

 absent in the species here studied. The posterior tentorial pits (ptp), from which 

 the internal posterior tentorial arms (pta) originate, are minute and placed on the 

 membrane on each side of the mouth opening. The posterior arms are connected 

 with each other by means of the transverse slender tentorial bridge (tb). The 

 anterior tentorial arms (ata) usually fuse just before meeting the cranial apophysis, 

 but in Ceroputo and Nairobia groups they are well separated ; the anterior tentorial 

 pits, therefore, are not visible externally. 



The hair-like setae are always present on the head ; in the Pseudococcus group 



