178 



The Orders of Insects 



been suggested, the Stone-flies being reckoned as 

 a distinct order by some naturalists (96). They 

 are here treated as a sub-order, which must be 

 regarded as not very nearly related to the other two 

 sub-orders recognised. 



Sub-Order A. Mallophaga. 



This division includes the " Biting- 

 lice." They are wingless 

 insects with elongate 

 flattened body and large 

 head. The feelers are 

 short with only three to 

 five segments, and the 

 eyes very degraded or 

 - altogether absent. The 

 mandibles are provided 

 with sharp teeth, but the 

 first pair of maxills are 

 reduced to conical lobes ; 

 the second maxilla are 

 fused together to form a 

 broad plate-like lower 

 lip. The prothorax is 

 always distinct, but the 

 other two segments of 

 the fore-body are usually 

 very small, the meta- 

 thorax being often united 

 with the hind-body, 



which consists of from eight to ten visible segments 



(3, 110). 



Habits. — The Mallophaga are entirely a parasitic 



group of insects, spending their lives among the 



plumage of birds or the fur of mammals, and feeding 



/I 



Fig. 97. — Pigeon-louse (Goniocotes com- 

 par, Nitzsch), Europe. Magnified 

 30 times. From Osborn, Bull 5 (n.s.) 

 Div. Ent. U.S. Dept. Agr. 



