234 THE COCCIDAE 



usually located midway between the vulva and the caudal mar- 

 gin, but in Gymnaspis they are superimposed ; in the Lepido- 

 saphini the anus is situated far cephalad of the vulva, the latter 

 is frequently located on a line drawn through the caudal margin 

 of the postgenacerores and tlie anus some distance cephalad of 

 the mesogenacerores ; in the Diaspidini the anus may be located 

 caudad of the vulva, superimposed, or cephalad, but is usually 

 placed near to or slightly cephalad of the vulva; in the Fioriniini 

 the anus is usually placed cephalad of the vulva, frequently about 

 its own diameter, rarely slightlj' caudad ; in the Aspidiotini the 

 anus is situated caudad of the vulva, the distance varj'ing with 

 the genus and the species, in some it is located adjacent to the 

 proximal ends of the median pair of lobes, in others midway be- 

 tween the vulva and the caudal margin, or nearer to the vulva. 

 In measuring this distance, where reference is made to the caudal 

 margin, the distal ends of the median pair of lobes is always used 

 and not the bases or proximal ends of these lobes. In making 

 such measurements account must be taken of the fact that the 

 anus is not always round, the length may be two or three times 

 the width, in all such cases it is the transverse diameter or width 

 that is used. 



The mesal portion of the caudal margin of tlie pygidium is 

 deeply emarginate in certain species. This is variously described 

 as emarginate, indented, notched, deeply concave, or semicircular- 

 ly or concavely hollowed out. This emargination involves more 

 than the median incisura, because it is frequently of such size 

 that the median lobes are situated for the most part within the 

 emargination. These lobes are usually strongly oblique, the lat- 

 eral margin of each is fused to the pygidium, and only a small 

 portion of the distal end of each median lobe projects bej'ond the 

 general contour of the pygidial margin. This emargination is 

 known as the median notch or pygidial incision. 



The dorsal surface of the pygidium cephalad of the anus 

 sometimes contains a reticulated area. This area may be of some 

 size and cover a considerable part of the cephalic portion of the 

 pygidium or it may be very small in extent. The reticulations 

 are closely crowded together and the appearance is due to the 

 thickenings of the margins of the small areas. Green has com- 

 pared the pattern of the reticulations to that of crocodile-leather. 

 Their pattern and shape are responsible for their name of lattice- 

 shaped thickenings. The functioning of these thickenings is not 

 clear and they have evidently arisen independently several times 



