876 SOME POINTS OF GENERAL INTEREST 
1 . P. cheopis is small and more yellow than brown in colour 
when compared with P. irritans. It was this feature that led 
Tidswell in Sydney to call it P. pallidus, thinking he was dealing 
with a new variety. 
2. The number of bristles on the head is greater in P. 
cheopis than in P. irritans , and the ocular bristle in cheo'pis is 
situated nearly on a level with the upper border of the eye ; 
while in P. irritans it arises nearer to the lower margin. 
8. The antipygidial bristle in P. cheopis is longer than that 
of P. irritans . 
