DIPTERA. 493 



deposit their eggs on the body of various herbivorous quadrupeds, it is in 

 woods and pastures that we must look for them. Each species of CEstras 

 is usually a parasite of one same species of some mammiferous animal, and 

 selects for the location of its eggs the only part of its body that is suitable 

 for its larvae, whether they are to remain there, or pass from thence to the 

 spot suited for their development. The Ox, Horse, Ass, Rein-deer, Stag, 

 Antelope, Camel, Sheep and Hare are the only quadrupeds yet known, 

 which are subject to be inhabited by the larvae of the CEstri. They seem 

 to have an extraordinary dread of the Insect when it is buzzing about them 

 for the purpose of depositing its eggs. 



The domicil of the larvae is of three kinds; we may distingush them by 

 the names of cutaneous, cervical, and gastric, as some live in the lumps or 

 tumours formed on the skin, others in some part of the interior of the head, 

 and the rest in the stomach of the animal destined to support them. 



CE. b&vis, De Geer. From six to seven lines in length, and densely pi- 

 lose; thorax yellow, with a black band; abdomen white at base, with a ful- 

 vous extremity; wings somewhat obscure. 



The female deposits her eggs under the hide of healthy Oxen and Cows, 

 of not more than two or three years of age. The consequence of this ope- 

 ration are tumours or lumps, on the internal pus of which the larvae feed. 

 Horses also are subject to them. 



The Rein-Deer, Antelope, Hare, &c., also nourish various larvae of CEstri, 

 but of a different species. 



(E. ovis, L. Five lines in length, and but slightly pilose; head greyish; 

 thorax cinereous, with elevated black points; abdomen yellowish, finely 

 spotted with brown or black; legs pale-brown; wings transparent. The 

 larva inhabits the frontal sinus of the Sheep. That of the species called 

 trompe, Fab. , is found in the same parts in the Rein-Deer. 



(E. equi, Lat.; Clarck. But slightly pilose, and of a fulvous brown; ab- 

 domen paler; two points and a band on the wings, black. The female de- 

 posits her ova on the legs and shoulders of Horses; the larvae inhabit their 

 stomach. 



The third tribe of the Athericera, that of the CONOPSARI^E, is the 

 only one of that family in which the proboscis is either always sali- 

 ent and siphoniform, cylindrical or conical, or setaceous. The re- 

 ticulation of the wings is the same as in our first division of the 

 Muscides. 



Most of these Insects are found on plants. They form the genus 



CONOPS, Lin. 



In Conops, properly so called, the two last joints of the antennae formed a 

 club, with a terminal stilet. 



C. rufipes; Fab. Black; abdominal annuli edged with white* base of the 

 abdomen and legs fulvous; edge of the wings black. 



