EXTERNAL ANATOMY OF INSECTS. 463 



been denominated % of the Arachnida, their mandibles. 

 The palpi are pediform, and the first joint of the coxa, 

 or hip, acts the part of a maxilla : — this is composed of 

 a single piece or plate, more or less oval or triangular, 

 sometimes straight and sometimes inclined to the labium, 

 with the interior extremity very hairy. The labium con- 

 sists also of a single piece, and is only an appendage of 

 the anterior extremity of the breast. The interior of 

 the mouth, or palate, presents a fleshy, hairy, linguiform 

 piece, which is usually applied to the internal face of the 

 labium. An opening is supposed to exist in its sides, for 

 the transmission of the alimentary juices b . If you ex- 

 amine the under side of the body of a scorpion, you will 

 find that not only the palpi, but the two anterior pair of 

 legs, by means of their coxa, are concerned in mandu- 

 cation : so that these insects have in fact three pairs of 

 maxillae — a circumstance that M. Savigny has observed 

 to take place also in the harvest-men (Phalangium L.) c . 

 The palpi of the scorpion, which may be called its hands, 

 like the anterior legs of the lobster and crab, terminate 

 in a tremendous chela or forceps, consisting of a large 

 triangular joint, armed at the end with a double claw 

 internally toothed ; the exterior one of which, contrary 

 to what takes place in the animals just named, is move- 

 able, and not the interior d . 



Havino- given you this full account of the trophi of 

 those animals that have all the organs of manducation 

 developed, I must next advert to those in which one part 



* N. Diet. d'Hist. Kat. ii. 276. b Ibid. 



- Ubi supr. 58. d Plate XV. Fig. 7- 



