EXTERNAL ANATOMY OF INSECTS. $63 
and become a kind of accessory Labium, Maxilla, §c. 
Thus in the Myriapods, the anterior pair of legs assume 
a Maxillary form and office*; the Prosternum those of a 
Labium?: zz the Arachnida, also, the anterior Coxe are 
accessory Maxillee. In this Class, likewise, as has been 
more than once observed’, the representatives of the in- 
terior pair of Antenne of the Crustacea, are thought 
to assume the form and the functions of suctorious Man- 
dibles *. 
ii. Facres (the Face). ‘The upper surface of the head *. 
It includes all the parts that lie between its junction 
with the Prothorax and the Labrum: viz. Nasus, 
: Postnasus, Frons, Vertex, Occiput, Gene, Tempora, 
Oculi, Stemmata, and Antenne. 
1. Nasus (the Nose). That portion of the face, often 
elevated and remarkable, situated between the La- 
brum, Postnasus, and Gene, and with which the 
Labrum articulates; called by Fabricius the Cly- 
peus*’. It includes the Rhinarium. 
A. Ruinarivum (the Nostril-piece). The space between 
the anterior margin of the Nasus and the Labrum, 
in which, in vertebrate animals, the nostrils are often 
situateds.—N.B. This is remarkable in some Peta- 
locerous beetles, as Anoplognathus. In Necrophorus, 
and some others, it ts membranous. 
2. Posrnasus (the Postnasus). That part of the Face 
immediately contiguous to the Antenne, that lies 
weeare Vil. Kye. 11, 13:9" EMibid. Pre. Tia": 
° See above, p. 18, &c. - 4 Plate VI. Fre: 107" 
© Ibid. Fic. 1, 4, 10.4. f Thid. a. 
© Ibid. of. 
