SUBFAMILY DIASPIDINAE 221 



It is a valvular structure through which the flexible penis can be 

 extruded. The wings, which are normally present and prominent, 

 are sometimes wanting or greatly reduced in size in certain indi- 

 viduals. 



The adult females vary greatly in form, size, and structure 

 in the different genera. The body may be elongate oblong, two or 

 three times as long as wide, linear, five or more times as long as 

 wide, oval or circular, varying from slightly longer than broad to 

 broader than long. 



The constriction between the head and prothorax in the female 

 is rarely if ever marked while those bounding the other thoracic 

 segments may be distinct, obscure, or wanting. The antennae are 

 at most represented only by unsegmented tubercles bearing a 

 single large seta and in some species a few small setae. These 

 tubercles are articulated to the cephalic part of the ventral aspect 

 near to each other and to the meson. The ocellanae are always 

 wanting in the second nymphal and adult female. The mouth- 

 parts are well developed. The rostrum consists of a single segment 

 which is globular in form. The rostralis is long and forms a 

 distinct rostral loop within the crumena except in individuals 

 where the rostralis has been pulled out of the crumena in removing 

 the specimen from the host-plant. The rostrum, rostralis, and 

 crumena are always associated with a well developed endoskeleton. 



The thoracic spiracles are always distinct and the spiracular 

 trachea connecting with each is modified into a distinct hour-glass 

 or trumpet-shaped cavaera. The mesothoracic spiracles are located 

 on each side of the attachment of the rostrum, while the meta- 

 thoracic spiracles are frequently located farther apart and about 

 as far caudad as the two mesothoracic spiracles are distant from 

 each other. This distance will vary slightly not only with the 

 species but with the different individuals of the same species. 

 When there are indentations in the lateral margin marking the 

 constrictions between the thoracic segments, the spiracles are gen- 

 erally located in line with these constrictions. It is doubtful if 

 these indentations represent the rudiments of the stigmatal clefts 

 and canellae, but in many species there are often a few spiracerores 

 associated with the spiracles, more frequently with the mesa- 

 thoracic than the metathoracic. 



The great majority of the structures used in distinguishing 

 and classifying the various species of Diaspidinae are located upon 

 the abdomen. Morphologists are fairly well agreed that the typical 



