THE COMMON RED-LEGGED LOCUST 



structures for sight, so that the whole may be regarded as 

 a mosaic of single eyes. In addition, there are simple eyes, or 

 ocelli (Fig. 2, 13), placed 

 in the form of a triangle 

 on the front of the head. 

 Notwithstanding these 

 two kinds of eyes, it is 

 doubtful whether the 

 locust is able to per- 

 ceive well the outlines 

 of objects, or to dis- 

 tinguish much except 

 light and movement. 

 The ocelli probably do 

 not perceive objects at 

 a greater distance than 

 a few inches, nor the 

 compound eyes at a 

 greater distance than a 

 few feet. It has been 

 surmised from the 

 structure of the com- 

 pound eyes that each facet perceives only a 

 field of vision. 



The Thorax. The first somite of the thorax, called the pro- 

 thorax (Fig. 2, 2), bears the first pair of legs. It is free from 

 the rest of the thorax. The dorsal surface (Latin, dorsum, 

 back) is thickened and raised into a ridge ; the sides (lateral 

 surfaces) are also thickened, and the whole forms a protective 

 shield or collar. The second somite, the mesothorax (Fig. 2, 3), 

 bears the second pair of legs ; to the third, or metathorax 

 (Fig. 2, 4), the last pair of legs is attached. Each leg is com- 

 posed of a number of divisions, or segments, of which the 

 principal are the thick femur (Fig. 2, 14, 15, 16 ; Fig. 3, 5) 



FIG. 1. Mouth-Parts of Red-Legged Locust, 

 x 4 



1, labrum; 2, mandible; 3, hypopharynx ; 4, first 

 maxilla with its palpus; 5, second maxillre 

 with palpi 



jmall part of the 



