TRIBE LEUCASPIDINI 259 



In all the species of the genus Leucaspis, so far as known, 

 the adult female completes its existence in a puparium. This 

 method of development is considered as a mark of the highest 

 type of specialization. The lines of modification of the pygidium 

 after the assumption of this method of development is apparent- 

 ly the same in most of the tribes. One change usually to be noted 

 is a modification and reduction of the groups of genacerores until 

 they are finally completely suppressed. An exception to this rule 

 is found in most of the species of this tribe. Although trans- 

 forming in a puparium, they have not only retained their gena- 

 cerores, but they are frequently represented by groups contain- 

 ing a considerable number of cerores. There may be the typical 

 number of groups, five, present or there may be additional groups 

 present until as many as seven additional groups can be counted 

 or the five groups may be combined into a single large inverted 

 U-shaped or crescentic mass or omnagenaceroris. 



The pygidial fringe of this tribe illustrates well some of the 

 stages in the modification of lobes and pectinae. The lobes are 

 modified not only in size and changed in shape, but are lost in 

 the adult females of certain species. The pectinae, which are 

 typically distapectinae in the second nymphal females, are great- 

 ly elongated in the adult female of many species. They are 

 slender in form with converging sides with blunt ends. These 

 vary in form from coarsely toothed to finely toothed, to the lack 

 of teeth, and eventually assume the form of plates. The number 

 of plates is greatly reduced in certain species while in other 

 species the pygidium appears with projections, pseudolobes, which 

 are asymmetrical not only in form but in arrangement. Some 

 of the pseudolobes resemble lobes and others pectinae or plates. 

 The pygidium of indica is of particular interest as illustrating 

 an intermediate stage of modification. The genacerores are want- 

 ing. The lobes, of which there are three distinct pairs, have been 

 modified into greatly elongated clavate structures. The projec- 

 tions between the lobes are broad structures with their distal 

 ends blunt without teeth. That these are pectinae or plates un- 

 dergoing modification is shown by their number and arrange- 

 ment, 2, 2, 3, 3, which is typical for the second nymphal stage of 

 loewi as figured by Newstead and of the large majority of gen- 

 eralized pygidia of other tribes. The position of the lobes and 

 the number of projections, pectinae or plates, between them is 

 more dominant than the form of these structures although the 

 dominance of the form of the lobes is generally more marked 



