374 EXTERNAL ANATOMY OF INSECTS. 
medial nervure; or in Orthoptera, &c. between the 
anal nervure and the posterior margin *. 
C. ArEo.z (the Areolets). The smaller spaces into 
which the wing is divided by the nervures. They 
include the Areole Basilares, Media, and Apicales. 
a. ArroLz Basiwares (the Basal Areolets). The pa- 
rallel areolets of the base of the wing °. 
b. ArroLt#2 Meni (the Middle Areolets). The areolets 
of the wing that lie between the basal areolets and 
the apical °. 
c. ArEoL® ApicaLes (the Apical Areolets). Those 
areolets of the wing that terminate in or very near 
the apex ¢. 
D. NEuR (the Nervures). Corneous tubes, for expand- 
ing the wing and keeping it tense, and to afford 
protection to the air-vessels—commonly called the | 
Nerves. They include the Neura Costalis, Post- 
costalis, Mediastina, Externo-media, Interno-media, 
Analis, Axillaris, and Spuria. 
a. Nevura Costauis (the Costal Nervure). The first 
principal nervure of the wing, close to or forming 
the anterior margin in Lepidoptera, Hymenoptera, 
and Diptera ; but sometimes remote from it in Teg- 
mina®. It includes the Phialum and Hamus. 
a DPuriaLum (the Phial). A little bag to receive fluid at 
the will of the insect, by which the weight of the 
wing is increased. It is found also in the under- 
wings in Coleoptera *. 
a Prate X. Fic. 2, 3. d-. » Ibid. Fic. 715. e-. 
° Ibid. f. * Ibid. g°. © Ibid. h°. 
€ Chabrier Sur le Vol des Insectes, Ann. du Mus. 3eme Ann. 428. 
4eme Ann: 325—. 3d Cahier 78. 
