228 Proceedings of the Royal Physical Society. 
pectinicornis (Fig. 6) the lacinial lobes are more rounded than in A. domesticum 
and the others. 
A fold running parallel to the stipes has been the subject of discussion by 
Perris. ; 
The apical joint of the maxillary palp bears a number of small papille. 
The Zabiwm consists of the fused second maxillz. It comprises :— 
The mentwm (m)—bearing the palps and ligula. 
The swbmentuwm (s-m)—an inferior or posterior piece. 
Below or behind the submentum and partly surrounding it is the 
Fig. 6. 
= 
Maxille and labium of Ptilinus pectinicornis. 
submental area, The labial palps are two-jointed, and as in the maxillary 
palpi their apical joints bear papille. 
The mentum bears a number of bristles along its upper margin. The 
submentum bears a group of bristles on each side. 
In Ptilinus pectinicornis (Fig. 6) the mentum is elongated and narrow. 
The submentum is not distinct from the submental area. The ligula is long 
and densely bristled. 
The Thorax. 
The thorax of the larva of A. domesticwm (Fig. 1) is made up of three 
segments—the first adjoining the head called the pro-thorax, a second the 
