MOUTH OF THE LOUSE. 



101 



pyles (m, minute orifices for the passage of the spermatozoa 



into the egg), which vary in form in the different species and 



genera; the opposite end 



of the egg is provided with 



a few bristles. The female 



attaches her eggs to the 



hairs or feathers of her 



host. 

 After the egg has been 



fertilized by the male, the 



blastoderm, or primitive 



skin, forms, and subse- 

 quently two layers, or em- 



b r y o n a 1 membranes, ap- m Mouth Parts of the Louse> 



pear; the outer is called the amnion (Fig. Il4, am), while the 

 inner visceral membrane (db) partially 

 wraps the rude form of the embryo in 

 its folds. The head (ok) of the em- 

 bryo is now directed towards the end 

 of the egg on which the hairs are situ- 

 ated ; afterwards the embryo revolves 

 on its axis and the head lies next to 

 the opposite end of the egg. Eight 

 tubercles bud out from the under side 

 of the head, of which the foremost and 



longest are the antennas (as), those succeeding are the mandi- 

 bles, maxillae, and second 



maxilla), or labium. Behind 



them arise six long, slender 



tubercles fornjing the legs, 



and the primitive streak 



rudely marks the lower 



wall of the thorax and 



abdomen not yet formed. 



Figure 115 represents the 



head and mouth parts 



of the embryo of the same 



louse ; vk is the forehead, 



or clypeus ; ant, the anten- 

 na); mad, the mandibles; 



max 1 , the first pair of maxillae, and max*, the second pair of 



118. Mouth Parts of Louse. 



117. Mouth Parts of Louse. 



