68 



ANIMAL BIOLOGY 



the grasshopper's range of vision compare with that of the 

 crawfish ? 



Are the antennae flexible ? What is their shape ? Posi- 

 tion ? Are they segmented ? Touch an antenna, a wing, 

 a leg, and the abdomen in succession. Which seems to be 

 the most sensitive to touch? The antennae 

 are for feeling; in some species of insects 

 they also are organs of hearing and smelling. 

 The mouth parts of a grasshopper should 

 be compared with the mouth parts of a bee- 

 tle shown in Fig. 113, since they correspond 

 closely. If the grasshopper is fed with a 

 blade of fresh grass, the function of each organ may be 

 plainly seen. It is almost impossible to understand these 

 functions by studying a dead specimen, but a fresh speci- 

 men is much better than a dry one. 



The upper lip, or labrum, is seen in front. Is it tapering 

 or expanded ? In what direction is it movable? The dark 

 pointed biting jaws (mandibles) are next. Are they curved 



FIG. 113. 



FIG. 114. a, FOOD TUBE OF BEETLE. 



b, gizzard ; d, intestine; c, biliary vessels. See Fig. 127. 



or straight? Sharp or blunt pointed ? Notched or smooth ? 

 Do they work up and down, or sideways ? The holding jaws 

 (maxilla), each with two jaw fingers {maxillary palpi), are 

 behind the chewing jaws. Why? The lower lip (labinm) 

 has a pair of lip fingers {labial palpi) upon it. The brown 



