388 INSECTS. DIPTERA, 



anterior part ; sides and posterior margin ferruginous ; abdomen 

 slender and ferruginous at the base, black and tumid at the ex- 

 tremity, with the margins of the rings ferruginous ; wings trans- 

 parent, with the exterior margin obscure from the base two-thirds 

 of the length ; balancers pale yellow. 6 lines long. Inhabits 

 Europe. Nouv. Diet. vii. 459. 



TRIBE III. (ESTRIDES. 



Buccal cavity sometimes inclosed by the skin, presenting two 

 tubercles, at others consisting in a small cleft ; proboscis in 

 those in which it is perceptible excessively small ; two palpi 

 in some, either isolated or accompanying the proboscis ; an- 

 tennae very short, inserted in a bilocular cavity. 



The CEstrides resemble the domestic fly in appearance, but the body has generally 

 coloured bands. The larvae live either on the exterior or within the skin of herbi- 

 vorous mammalia, and sometimes upon man. When about to change into the pupa 

 state, they quit their dwelling, and conceal themselves in the ground or at its surface, 



I. With a proboscis. 



Gen. CUTEREBRA, CEPHENEMYIA. 



II. Without a proboscis ; two palpi. 



Gen. CEDEMAGENA. 



III. Neither proboscis nor palpi ; a buccal cleft. 

 Gen. HYPODERMA. 



IV. Neither proboscis nor'palpi ; buccal cavity short ; two vestiges of palpi on the 

 membrane. 



Gen. CEPHALEMYIA, (ESTRUS. 



Gen. (ESTRUS, Lin. Lat. Gasterophilus, Leach. 

 Wings with all the hinder cells terminal ; thorax smooth ; ex- 

 tremity of the abdomen inflexed, in the female much elon- 

 gated and attenuated ; eyes distant. 



The larvae inhabit the stomachs of herbivorous quadrupeds, and are called JBots ; 

 the perfect insects Bot-flies. 



QE. equi, Fab. Head yellowish white, with an impression in the form 

 of an angle on the vertex, and including the smooth ocelli ; thorax 

 yellowish, with two bundles of elevated hairs upon a blackish 

 point j abdomen reddish, with two blackish spots ; wings with a 

 band in the middle and two small blackish points at the extremity 

 Inhabits Europe. B. Shaw, vi. pi. 102. 

 The female deposits her eggs on the legs and shoulders of horses, parts which are 



often licked by the animals, and are thus taken into the stomach. 



TRIBE IV. MUSCIDES, Lat. 



Antennae of two or three joints, generally of three, the last flat- 

 tened, with a simple or plumose seta on its back near the base; 

 proboscis membranous, bilobiate, geniculate, retracted into 

 the buccal cavity in repose, and inclosing in a groove above 

 a sucker of two setae. 



The Muscides, forming part of the Linnaean genus Musca^ have the general ap- 

 pearance of the domestic fly. Their head is hemispherical, with large reticulated 



