280 THE AMERICAN MONTHLY [December, 



jointed or furnished with a palpus, lying just behind the labrum. 

 The mouth-parts are used in biting hard sorts of food, e. g.^ leaves 

 of grass,* etc. 



The thorax (Fig. i) consists of two parts, which are separate ; 

 one in front, the t>rothorax^ connected to the head by a fleshy 

 short neck, and the other, the meso-?7ieta-thorax^ bearing the 

 xvings and closely joined to the abdomen. The prothorax is 

 covered with a saddle-shaped piece above and on the sides, called 

 ihe pro-Jiotnm ; and a narrow strip below, called \\-\& pro-sternum. 

 At the junctions of these are sockets to which the legs are attached. 

 The legs consist of movable pieces, called joints, whose names 

 are as follows: i,the coxa^ next the body ; 2^ the troc/ianter \ 

 3, the femur^ long and narrow ; 4, the tibia, also long and 

 narrow; 5, the tarsus, consisting of four small joints ending in 

 two claws. The meso-meta-tJwrax bears two pairs of wings and 

 two pairs of legs. It consists, so far as concerns the external 

 covering, of two pieces above, called terga, side pieces which 

 slant obliquely, downward and backward, and show a line partly 

 dividing them into two portions, and a central piece, the sternum, 

 which transverse lines divide into 3 portions, one the nicso-ster- 

 num, behind it the meta-sternum, and still behind it the first ab- 

 dominal sterniim. The meso-meta-thorax bears two pairs of 

 legs and two pairs of wings. The former present the same joints 

 as the leg of the prothorax, but the meta-leg is different from the 

 others in that the femur and tibia are larger and longer, the femur 

 containing the muscles which move the tibia. The wings are 

 attached at the margins of the meso- and meta-terga. They are 

 not alike, the front wings being oblong and stronger, while the 

 hind wings are triangular and delicate, and when not in use folded 

 like a fan beneath the former. The front border of the hind 

 wing is stouter than the hind border. Both wings are marked by 

 systems of lines called veins, which branch out into ?ix\er veinlets 

 and strengthen the delicate tissue of the wing. Minute openings, 

 called spiracles (Fig. 3). which admit air to internal breathing 

 tubes, are located in the side wall of the thorax, just over the coxae 

 of the different legs. 



The abdomen consists of a number of joints, somites, most of 

 them alike and presenting a dorsal piece, the tergum, joined by a 

 fold, the ple2ir7ini, to a ventral piece, the sternum. The front 

 abdominal somite is unlike the others, its tergum being more like 

 that of the meso and meta-thorax and its sternum being separate from 

 the tergum and joined with those of the meso-meta-thorax. The 

 side wall of this incomplete abdominal somite bears the ear (Fig. 

 3), which shows externally as an oval thin membrane. Behind 

 this first incomplete abdominal somite are 8 more somites, which 

 are alike, each one having its tergum and sternum and pleural fold. 

 In the lower front portion of each tergum is located a spiracle. 



*To study this chapter from the specimen it should be read, ver fyiiig point hy poii't upon 

 a specimen drawing and indexing everything observed. 



