126 MORPHOLOGY AND TAXONOMY OF ADULT MALES 



anterodorsal bulge, large numbers of setae, etc., were grouped together. The validity 

 of these groups were then tested by calculating the number of characters shared by 

 the group as a whole, and by pairs of genera from different groups. For the purpose 

 of these calculations all characters were treated as of equal weight and importance. 

 It was found that the family could be divided into four groups of genera, which can 

 conveniently be called the EULECANIUM group, the ERIOPELTIS group, the 

 INGLISIA group and the COCCUS group. In the following discussion the refer- 

 ences to suprageneric groups refer to these groups and three aspects will be discussed : 



(a) the characters which are of taxonomic importance and the levels at which 

 they appear to be valid, 



(b) the classification and interrelationships within the family, and 



(c) the relationship of this family with other subdivisions of the Coccoidea. 



It must be stressed here that only a small number of species were studied. All 

 the statements and conclusions are therefore tentative and some of them are bound 

 to be altered or even abandoned as more information becomes available, particularly 

 because the grouping suggested from a study of the male does not conform with the 

 classification based on the female. 



Taxonomic Significance of the Characters 



All the characters which appear to be of some taxonomic importance are listed in 

 Tables I-IV. The characters which at this stage of research were found useful for 

 separating the groups of genera, genera and species are discussed below and listed 

 in detail in Table I. 



The size and general appearance show considerable variation within the family. 

 Broadly speaking, the size is characteristic of species or groups of species but the 

 actual size may vary considerably within one species. Thus specimens of P. corni 

 from different localities (Poland, Russia and Yugoslavia) showed large differences, 

 e.g. those from Yugoslavia were about f the size of those from Poland, the Russian 

 ones being intermediate. Apart from local climatic conditions, this may be due to 

 the effect of the host plant, which has been shown to influence the size of the females 

 of this species (Habib, 1953 ; Kawecki, 1958a) ; Bustshik (1958) suggested that the 

 effect of the host plant caused size variation in males of some Diaspididae, whereas 

 Ghauri (1962), having found males of distinctly different sizes on the same host 

 plant, mentioned genetic polymorphism as a possible cause. The size is therefore 

 considered to be of rather limited significance. The general " hairy " appearance 

 of the body can be used to separate groups of genera. 



The Head. 



The shape of the head is characteristic of groups of genera, thus it is flat in the 

 ERIOPELTIS group (Text-figs. 25, 28) and elongated dorsoventrally in all the 

 other groups except Genus A (Text-fig. 21) where it is rounded. The peculiar 

 condition where the anterodorsal bulge is pronounced and the medioventral bulge 

 drawn far back, is characteristic of most of the COCCUS group (Text-figs. 32-40). 

 The conditions of the ventral part of the midcranial ridge separate groups of genera, 



