18 MORPHOLOGY AND TAXONOMY OF ADULT MALES 



reached the cranial apophysis and apparently the anterior arms have completely 

 fused with the " dorsal " ones. No sclerotized ventral cavity as illustrated by 

 Theron (1958, fig. 22) is apparent and the illustration does not seem to agree with 

 his description and fig. 13, where the ventral cavity is shown to be situated behind 

 the preoral ridge. The tentorium has not been described by other workers, but 

 from an examination of specimens in which the head is distorted, it is clear that 

 what Borchsenius (1957) called the " cephalic sclerotized arch " and Bustshik & 

 Saakjan-Baranova (1962) regarded as the occipital ridge, is in fact the tentorial 

 bridge. 



Chaetotaxy 



Two distinct types of setae, similar to those found in Pseudococcus (Giliomee, 

 1961), are present on the head of male Coccidae. They are: 



(i) a thick-set, fleshy type (fs), which has a rather blunt apex and the setal mem- 

 brane not surrounded by a distinct basal ring, and 



(ii) a slender, hair-like type (hs) which has an acute apex and the setal membrane 

 surrounded by a strong basal ring. 



Generally the hair-like setae occur in all the species in comparatively small 

 numbers and when only these setae are present the head appears to be rather bare. 

 In those species where fleshy setae are also present the head has a " hairy " appear- 

 ance, the number of these additional setae being generally much larger. 



The setae on the head are arranged in the following groups: 



(i) Dorsal head setae (dhs), which are situated on the median crest, but may also 

 occur on the surrounding membrane in front of the dorsal simple eyes. This 

 group consists either of hair-like setae only (the EULECANIUM and ERIOPELTIS 

 groups) or of both fleshy and hair-like ones (the INGLISIA and COCCUS groups). 

 The number of hair-like setae, which are present in all the species, varies from 1-7 

 (average 5) in P. acericola to 16-19 (average 17) in P. corni ; the number of the 

 additional fleshy setae, in the species in which they occur, varies from 4-1 1 (average 

 7) in /. theobromae to 26-42 (average 35) in C. hesperidum. 



(ii) Dorsal ocular setae (dos), which are found on each side on the dorsal part of 

 the ocular sclerite between the dorsal simple eye and the postocular ridge, and 

 consist of both fleshy and hair-like setae. The total numbers of these setae are 

 small and variable and the proportion of the two types of setae is also variable 

 within the species. 



(iii) Ventral head setae (vhs) : This group occurs on the ventral and lateral parts 

 of the ocular sclerite and may extend up to the lateral arms of the midcranial ridge. 

 In the COCCUS and INGLISIA groups, but not in the other species examined, 

 the setae also occur between and behind the ventral eyes. In most species of the 

 EULECANIUM group the setae are situated only on or anterior to the level of 

 the preocular ridge. In a few species (Genus A, S. prunastri, L. luzulae; Text-figs. 

 20, 22, 27 ; C) one pair of median hair-like 3etae is distinctly longer than the other 

 setae. The hair-like setae occur in all the species in small numbers, varying from 

 1-2 (average 1-3) in N. abietis to 7-17 (average 12) in E. ? festucae, but in R. spiraeae 



