438 EXTERNAL ANATOMY OF INSECTS. 
the base of the mandible*; in the second it is broader, 
straighter, and fringed internally and at the end with 
hairs; and in this at first it wears the appearance of be- 
ing attached laterally tc the mandible under the tooth», 
but if closely examined you will find that it is separate : 
in Creophilus mazillosus it is broader. ‘This is the part 
I have named prostheca. It is perhaps useful in prevent- 
ing the food from working out upwards during mastica- 
tion. 
5. Maxille*. The antagonist organs to the mandible 
in the lower side of the head, are the under-jaws, or maz- 
ille—so denominated by the illustrious Entomologist of 
Kiel. Linné appears to have overlooked them, except 
in the case of his genus Ap7s, in which he regards them, 
and properly, as the sheath of the tongue. De Geer 
looked upon them in general as part of the apparatus of 
the under-lip or 7abium ; and such in fact they are, as 
will appear when we consider them more particularly. 
Fabricius has founded his system for the most part upon 
these organs, the principal diagnostic of ten out of his 
thirteen Classes (properly Orders) being taken from 
them; and in the modern, which may be termed the 
eclectic, system, although the Orders ave not founded 
upon them, yet the characters of genera, and sometimes of 
large tribes, are derived from them: and as they appear 
*Prare XIII. Fic. 7. c’. Dr. Leach has, by mistake, taken Staphy- 
Anus cyancus for the type of Ocypus ; the real type is St. similis, F. 
St. brunnipes, punctulatus, and all those that have the last joint of 
the labial palpi more or less securiform, and the mandibles slender, 
belong to it. Sé. cyaneus is a Goerius, taking St. olens for the type 
of that genus.—K. 
* Oliv. Ins. no. 42. Staphylinus, t. 1. f. 1. b. 
* Prares VI. VIL XXXVI. d’. 
