128 MORPHOLOGY AND TAXONOMY OF ADULT MALES 



The Thorax. 



Prothorax. The absence or presence of certain groups of setae and pores can be 

 used to separate genera ; a reticulated prosternum is characteristic of Coccus 

 hesperidum and a spinose prosternum of the INGLISIA group. The condition of 

 the median ridge of the prosternum varies too much to be of practical use as it may 

 be complete or any section of it reduced within the same species. 



Mesothorax. This provides a number of important characters. The shape of 

 the mesoprephragma, the condition of the reticulation on the prescutum and the size 

 of the membranous area of the scutum can be used as supplementary characters to 

 separate genera and species. A tubular scutellum is characteristic of the ERIO- 

 PELTIS and COCCUS groups and the two closely related genera Ctenochiton and 

 Filippia. A basalare joins the pleural wing process to the mesepisternum in all 

 the groups except the COCCUS group, where this structure is vestigial or absent. 

 The condition of the median ridge of the basisternum separates groups of genera, 

 genera and species. As is the case with the head, the setae of the mesothorax 

 (and metathorax) provide a number of very useful characters. The number of 

 fleshy and hair-like scutal setae separates certain genera ; the presence of fleshy 

 postmesospiracular setae separates the COCCUS and INGLISIA groups from the 

 EULECANIUM and ERIOPELTIS groups ; the setae on the postalare and 

 basisternum can be used to distinguish genera. 



Metathorax. The condition of the metapleural ridge and suspensorial sclerites is 

 correlated with the absence or presence of the halteres (q.v.). When the halteres 

 are absent, the metapleuron is reduced and the suspensorial sclerites absent. The 

 presence of antemetaspiracular and dorsospiracular setae differentiates the 

 INGLISIA and COCCUS groups, while the variation in the number and type of 

 postmetaspiracular, anterior metasternal and posterior metasternal setae can be 

 used to differentiate groups and genera. 



The fore wings vary from being long and narrow in the ERIOPELTIS group to 

 short and broad in the COCCUS group ; in the EULECANIUM group this variation 

 in shape can be used to separate genera. The absence of halteres is characteristic of 

 the ERIOPELTIS, INGLISIA and COCCUS groups and the genera Phyllostroma 

 and Sphaerolecanium. Sulc (1908) used this characteristic to define genera. The 

 differences in the number of alar and haltere setae can be used to differentiate genera. 



The characters provided by the legs seem to operate on all taxonomic levels. 

 Some characters are constant within one or two of the groups, but differentiate 

 genera and species in others, e.g. (i) the length of the hind leg and the length of the 

 body is subequal in the ERIOPELTIS and INGLISIA groups, but differences in 

 the ratio between these two measurements separate genera in the EULECANIUM 

 group, and the two species of Pulvinaria in the COCCUS group, (ii) The coxal 

 bristles are absent in the ERIOPELTIS group and some of the genera of the 

 EULECANIUM group, but they are present in other genera of the EULECANIUM 

 group, in the INGLISIA group as well as in the COCCUS group (except Ceroplastes 



