208 



INTRODUCTION TO ZOOLOGY 



CHAP. 



labium or " lower lip," which bounds the mouth on the lower 

 side. The labium also bears a pair of processes known as the 



nd' 



FlG. 139. The Mandible, Maxillae, and Labium of a Cockroach. 

 mnd, mandible ; a b has been removed from a' b' ; mx, maxilla ; mx.ls, maxillary 

 lobes ; mx.palp, maxillary palp ; m, mentum bearing the labial palp, Lp, and 

 the labium, Lb. The central lobe of the labium, the lingua, can be faintly seen. 



labial palps, and attached to it is a central lobe known as 



the lingua or tongue. 



In different insects, with different feeding habits, these 



various mouth-parts be- 

 come modified to suit the 

 food in each case, but 

 always the same parts can 

 be recognised, namely, 

 the single upper lip 

 (labrum), the pair of hard 

 jaws (mandibles), the 

 pair of soft jaws (first 

 maxillae), and the lower 

 lip, or labium, with its 

 palps. 



Of all the 

 The Eyes of i t 

 Insects. s P eclal 



tures found 



in insects, the most 

 peculiar and wonderful 

 are perhaps the large 



compound eyes, which 

 ^ ^^ g ^ ^ 



insects, although simple 



eyes may also occur. 



o.n. 



FIG. 140. Section through the eye of a 



Bee. 



o.n.. Optic nerve ; I, lens ; c, cones ; r, rods ; 

 Ji. hair. 



