EXTERNAL ANATOMY OF INSECTS. 427 
like the head of a hatchet ?; and at others it resembles 
the moon in her first quarter®. In the great dragon-fly, 
or demoiselle if you prefer the gentler French name, 
(4Hshna) the labial palpi, which are without any visible 
joints, are terminated by a minute mucro or point*. 
With regard to their direction and flexure, they fre- 
quently, as in the instance just mentioned, turn towards 
each other, and lie horizontally upon the end of the 
labium. Sometimes, as in the Cicindelida, they appear 
to point towards the tail of the insect, the last joint rising, 
and forming an angle with the rest of the feeler. In other 
instances they diverge laterally from the Jabium, the last 
joint turning again towards it at a very obtuse angle. 
4. Mandibule *.— Having considered the analogues of 
the /ps in our little beings, I must next call your atten- 
tion to the representatives of the yaws. ‘The vertebrate 
animals, you know, are mostly furnished with a single 
pair of jaws one above and the other below, in which the 
teeth are planted and which have a vertical motion. But 
insects are furnished with ¢wo pair of jaws, a pair of 
upper-jaws and a pair of under-jaws, which have no 
teeth planted in them, and the motion of which is hori- 
zontal.—I shall begin with an account of the upper-jaws. 
These by modern Entomologists, after Fabricius, are de- 
nominated mandibles (mandibula): a term appropriated 
by Linné to the beaks of birds. The upper-jaws of in- 
* Prare XIII. Fie. 2. Linn. Trans. xii. t. xxi. f. 6. b. 
» This is the case with Oxyporus, Plate XIII. Fic. 4. 
© Prate VI. Fic. 12. b!. Latreille (NN. Dict. d’ Hist. Nat. xvii. 
#45,) seems not to regard these as palpi; but from their tubular form, 
and insertion in the socket of the labium, it is clear that they ought 
to be so considered. 4 Prates VI. VIL. XXVI. c'. 
