STKITTI "i:i-:s rsi:i> IN CLASSIFICATION. !> 



cust, as well as in oilier < )rthoptera, depend very largely upon 

 Hie nature of the food, as Iliese organs serve no! only to sei/e and 

 hold the food in the nionlli. hnl also as accessory jaws, aiding the 

 mandibles in rendering I he food more suitable for swallowing. 

 Their palpi are not only organs of loiich, but in many cases ad 

 as hands in helping lo |rehend and carrying morsels of food to 

 I he mouth. 



Above the clypeus. is a ridge extending upward along the 

 median line of the face to the vertex. This is I he /'roii/u! coxta, 

 and its characters are often used in classification. In one species 

 it may be sulcate or grooved, in another, flat. Its edges, or <-<irin<r 



may be parallel the full length or may diverge 

 or converge. Its width and prominence are 

 also often mentioned. 



The region on the side of the head, behind 

 the eye and above the base of the mandibles, is 

 the cheek or f/ciui it/en.). To ;' r wall is 



attached the large muscle which moves the 

 mandible. 



The eyes of a locust are five in number, two 



of'hfad 3 ' ( \fter fnT ' ;11 '.- ( ' '<>iu] touiid ones and three 1 small, simjile 

 s ei '-) ones. The compound eyes are present in all 



Orthoptera. In the locust they vary in shape, but for the most 

 part are oval, and are located on the upper portion of the sides 

 of the head. Each is made up of many thousands of six-sided 

 facets or lenses, in each of which a single filament of the ontic 

 nerve 1 ends. The simple eyes or ore/// (oc.) are absent in some 

 Ortlioplera, as the Tettigoniidae, some of tlr> (Jryllidae and the 

 females of some Mantidae, but are present in the locust. Two of 

 them are situated just above the base of the antennae, close to tli- 

 inner margins of the compound eyes, while the third is located 

 near the middle of the frontal costa. Their position varies in the 

 different families of Orthoptera, and there are but I wo in Hi" 

 (iryllotalpinte or mole crickets. 



These ocelli are thought to be inherited from I he obscure eyes 

 of the worm-like ancestry of the locust, while the many facetted 

 comjiound eyes of insects and crustaceans have been evolved to 

 satisfy the needs of the more recent existence of these groups. 



The <intcnn<r tnt.) of the locust are simple, many jointed 

 appendages, localed on the face between the eyes and articulating 

 with the head by a ball and socket joint. They are principally 

 organs of touch, but are also supposed to contain the nerves of 



