— i7 — 



Review. — The mouth-parts consist of an upper-lip, la- 

 brum ; and under-lip, labium ; two pairs of jaws acting later- 

 ally between these lips ; and a tongue-like organ, hypo- 

 pharynx. The cephalic pair of jaws is called the mandibles ; 

 the caudal pair, the maxilla'. 



Note. — The natural attitude of the head of a locust is such 

 that the labrum and labium appear to be fore and hind lips respec- 

 tively ; and the mandibles and maxilla, fore and hind pairs of jaws. 

 But when the mouth is in its typical position, at the cephalic end of 

 the body-axis, the labrum is an upper-lip, the labium an under-lip, 

 the mandibles, the upper jaws, and the maxillae the lower jaws. 



Each maxilla consists of four primary and two secondary 

 parts. The primary parts are the eardo, slipes, lacinia, and 

 palpifer ; the secondary parts are the galea and maxillary 

 palpus. 



The labium consists of the submentum, mentum, ligula, 

 two palpigers, and two labial palpi. 



PARTS OF THE THORAX. 



Division into segments. — The thorax consists of three 

 segments. The cephalic or first segment is named the pro- 

 thorax ; the second or intermediate, the mesolhorax ; and 

 the third or caudal, the mcta thorax. 



These divisions of the thorax can be easily recognized by 

 the appendages they bear. To the prothorax is articulated 

 the first pair of legs ; to the mesothorax are joined ' the 

 second pair of legs and the first pair of wings ; and to the 

 metathorax, the third pair of legs and the second pair of 

 wings. 



PROTHORAX. 



Dorsal Part (Pronotum). — That which may be properly 

 termed the dorsal part of the prothorax is a large sunbonnet- 

 shaped piece which covers the greater portion of the sides as 

 well as the dorsal surface of this segment. This piece is 

 called the pronotum. 



