228 THE COCCIDAE 



lobes. The lobe cephalad of each second incisura is a second lobe, 

 that ceplialad of a third incisura is a tliird lobe, that cephalad of 

 each fourth incisura is a fourth lobe, and that cephalad of each 

 fifth incisura is a fifth lobe. The lobes cephalad of each median 

 lobe are sometimes numbered, beginnin": with the second lobe, as 

 the first lateral lobe, second lateral lobe, third lateral lobe, etc. 

 The lobes of the two sides are grouped together in pairs and des- 

 ignated as the second, third, fourth, and fifth pairs of lobes. The 

 maximum number of pairs of lobes is five, when there is more 

 than this number, the cephalic so called lobes are lobe-like lata- 

 dentes. The usual number of lobes is three, two, or a single pair. 

 The median lobes are generally the broadest and longest and each 

 successive pair is smaller and smaller until it becomes difficult to 

 distinguish the greatly reduced lobes from the latadentes. The 

 number of latadentes is greatly increased in certain species or 

 until such species are said to have ten or more pairs of lobes 

 present. A projection is not considered as a lobe in the follow- 

 ing descriptions unless it projects beyond the general outline of 

 the margin of the pygidium and has associated with it the other 

 structures of the pygidial fringe, plates and pectinae, which are 

 usually associated with lobes. The lobes when greatly reduced 

 in size frequently become narrower and in certain species are 

 long, blunt or pointed, spear-shaped projections. The lobes, even 

 when greatly reduced or plate-like in form, are never provided 

 with oraceratubae. The median lobes are sometimes adjacent on 

 the meson so that the median incisura is linear or they may be 

 fused for a part of their length so that it is represented as a 

 distinct notcli or they may be completely fused forming a single 

 lobe and effacing the median incisura. 



The lobes vary considerable in form. The simplest type is 

 where the margin of the lobe is without indentations and in such 

 cases is said to be entire. Where there is one or two indenta- 

 tions in the distal portion, the lobe is said to be notched. The 

 notch on the mesal side of the lobe is the median or mesal notch 

 and the one on tlie lateral side is the lateral notch. Either the 

 mesal or the lateral notch may be wanting. When there are a 

 few notches, more than two in the margin of the lobe, it is said 

 to be crenulate and when there are many notches to be serrate. 

 The notches in the crenulate or serrate lobes are always smaller 

 than in the ordinary notched lobes. A lobe may be divided into 

 two distinct parts bj^ an incision, when it is said to be incised or 



