576 MODERN CLASSIFICATION OF INSECTS. 
guished from all the other Athericera by having the mouth completely 
obsolete, no other traces being visible except two or three minute fleshy 
tubercles (fig. 132.17. front of head of Gast. Equi), except in the 
genus Cephenemyia Laér. (CZstr. Trompe), in which both the palpi and 
proboscis are visible. In Cuterebra, also, the proboscis is distinct and 
retractile. The antenne are very short ; the terminal joint rounded, 
and emitting a dorsal seta, thickened and articulated at the base (fig. 
132.18.) ; the wings are divaricate, the alulets very large, hiding 
the balancers. The nervures are few in number, in some they ex- 
tend to the tip of the wing, as in Gasterophilus Equi; in others they 
form cells, having the external nerve running parallel to the margin 
of the wing. These insects, whose habits are so formidable, and 
whose economy is so extraordinary, have the appearance of large hairy 
flies, the hairs being often coloured in transverse bands. 
Malpighi, Vallisnieri, Réaumur (JZém. tom. iv. mém. 12. pl. 34—38., 
and tom. v. pl. 9.), De Geer (Mém. tom. vi. tab. 15.), and Fischer 
devoted considerable attention to the elucidation of the natural his- 
tory of this genus, but it is to our own countryman, Bracy Clark, that 
we are indebted for a history of many of the species of this family, 
which leaves nothing farther to be desired. 
Each species of Céstrus is parasitic upon a peculiar species of 
mammiferous herbivorous animal, and selects, with wonderful instinct, 
as the spot in which to deposit its eggs, that portion of the body of the 

Ditto, An Essay on the Bots of Horses and other Animals, 4to. 1815.—Ditto, 
on the Insects called Oistros by the Ancients, in ditto, tom. xv. 1827. 
Mac Leay, on the Insect called Oistros by the ancient Greeks, and Asilos by the 
Romans, in ditto, tom. xiv. 1824. —Ditto, on the Cistrus of Mr. Bracy Clark, 
in Zool. Journ. tom. i. and vy. 
Keferstein. Remarques sur ]’Oistros des Anciens. Isis, 1827. 
Leach, on the Arrangement of the Ciéstrideous Insects, in Wernerian Trans. 1817. 
Isidore Geoffroy Saint Hilaire. Report on Trois Notices rélatives a l’Existence de 
l’Cstre chez 1 Homme, in Ann. Soe. Ent. de France, tom. ii. 1833. 
Metara. WHist. de deux Larves d’Cistres extraites de 1’Oreille dun Paysan, in 
Mém. de Zool. Médicale. 8vo. Rome, 1835. 
? Vom QCséstrus, &e. On the Cstrus which attacks Man in Peru (in 
Neuen Nord. Beytr. band 1.). 
Schreder. Organ. interne de la Larve de ’Cistre de Cheval, in Ferussac Bull. 

1831. No. 1. . 
Numan. Ueber die Bremsen Laryen, im Magen der Pferde. 8vo. 2 pl. Berlin, 
1837. 
And the general works of Meigen, Curtis, Wiedemann, Macquart, Fabricius, §c. 
