280 THE AMERICAN MONTHLY [December, 



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

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

 of grass,* etc. 



The tho7'ax (Fig. i) consists of two parts, which are separate ; 

 one in front, the profhorax^ connected to the head by a fleshy 

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

 ivings and closely joined to the abdomen. The prothorax is 

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

 the pro-fiot7it7i ; and a narrow strip below, called ihe pro-ste7-7i7i777. 

 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 bodv ; 2^ the t/-oc/ia7-iie7- \ 

 3, the femii7'^ long and narrow ; 4, the tibi'a, also long and 

 narrow; 5, the ia7-sus, consisting of four small joints ending in 

 two claws. The i7ieso-7neta-thorax bears two pairs of wings and 

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

 covering, of two pieces above, called tc7-ga^ side pieces vv'hich 

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

 dividing them into two portions, and a central piece, the ste/- 717177) ^ 

 which transverse lines divide into 3 portions, one the 777cso-sre7-- 

 77717/7^ behind it the 777eta'Ste7'n7i777^ and still behind it the first ab- 

 do772i7ial stei-7771777. 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 diflerent 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 vei7ts^ which branch out into ^\~\^x ve777lets 

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

 called spi7-acles (Fig. 3), whiclr admit air to internal breathing 

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

 of the diflerent legs. 



The abdo777f7i consists of a number of joints, so77/7tcs^ most of 

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

 fold, the ple7i7'7i777^ to a ventral piece, the ste/'7i7i777 . 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 ca/- (Fig. 

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

 this fii'st incomplete abdominal somite are S 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 ihe specimen it should be read, vcr fyin^ point liy poi.\t upon 

 a specimen drawing and indexing everything observed. 



