DIPTERA. 633 



Giimnosoma, Meig., has the abdomen vesicular, witli indistinct articulations, and the antennaj as long as 

 the head. 

 Cistogaster, Latr., has the abdomen similar, but the antennae much shorter. 

 Phasia, Jleig., has the abdomen very flat and semicircular, and the tibiae but slightly bristly. 

 Trichiopoda, Latr., has the abdomen flat but oblong, and the hind tibiae with a row of lamelliform bristles. 

 Sometimes the face has two rows of long bristles, like moustaches, two being larger than the rest. 

 The three following have the wings vibratile, and the abdomen narrow and elongate ; the antennae are not 

 shorter than the face. 

 Lophosia, Meig., has the last joint of the antenna^ forming a large triangular palette. 



Oci/ptera, Meig., has the third joint of the antennas seldom much larger than the preceding, and forming a linear 

 or oblong square. M. Dufour has observed the transformations of tvvo species ; the larva of 0. casslda, residing 

 in the visceral cavity of Cassida bicolor, and that of O. bicolor, in the same cavity of Pcntatoma prisea : both these 

 larvae feed on the fatty matter of the insects they infest ; their bodies are oblong, soft, whitish, perfectly glabrous 

 and contractile, and terminated by a sort of siphon one third of the length of the body, of a more solid consistence, 

 and unchangeable in its form, with two hooks at the tip : the posterior extremity of this siphon, occupying one 

 of the metathoracic spiracles [of the insect infested], and in contact with the air, enables the parasite to respire. 

 Neither antenna; nor eyes have been observed. It is in the same situation that the larva changes to the pupa state. 

 This [or rather the old larva skin] is ovoid, without any trace of segments, with several tubercles at one end. It 

 quits its abode before assuming the perfect state, either without destroying the insect, or the larva infested, or 

 after it has killed it. 



Melanophora, Meig., has the antenna; much shorter; the antennas not extending lower than the middle of the 

 face ; the outer terminal cell is more advanced posteriorly than the inner one. 

 The abdomen of the other Creophila is but little elongated, triangular; and the wings are not vibratile. 

 Phania, Meig., has the abdomen 4-jointed ; the tip being elongated, narrowed, and folded beneath ; the third 

 joint of the antennas is long and linear. 



Xi/sta, Meig., has the abdomen 5- or 6-jointed, and the antennae short, with the last two joints nearly equal ; the 

 hind tibiae are rather curved, compressed, and ciliated. 



Tachina, Fabr., has the abdomen 4-jointed, but not recurved at the tip ; the antennae as long, or nearly as long, 

 as the head ; the last joint longer than the preceding. Some of the species, forming a peculiar group, live whilst 

 larvae in the bodies of difterent caterpillars, which they destroy. 



We now pass to Creophilae which have the seta of the antennae evidently villose or plumose ; the third joint 

 always forms an elongated palette, and is longer than the preceding joint. 

 Dexia, Meig., has the habit of Ocyptera, with the abdomen narrow and elongated, especially in the males. 

 Musca proper {Mesembrina, Meig.), has the abdomen triangular, the eyes contiguous, or very close together in 

 the males. Here are to be arranged the majority of the flies of which the larvae feed upon meat, carcases, &c., and 

 others in manure. They have all the form of soft worms ; whitish in colour ; destitute of feet ; thickened and truncate 

 at the posterior extremity, and pointed at the other end, where are one or two hooks, with which these larvae gnaw 

 their food, and of which they hasten the corruption. They undergo their changes in a very few days [in the 

 summer] ; the females have the extremity of the body narrowed, and elongated into a tube, to enable them to bury 

 their eggs. Musca vomitoria, Linn., the Common Meat Fly, with the forehead fulvous ; the thorax black, and ab- 

 domen blue, with black marks. It possesses a remarkably fine sense of smelling, and makes a loud buzzing noise, 

 when it enters our houses in order to deposit its eggs on meat. Deceived by the odour of Arum dracunculus 

 w hen in flower, it sometimes deposits its eggs in that flovver ; wlien ready to assume the pupa state, it quits its food 

 and descends into the earth, or else undergoes its change in some dry and retired situation. M. domestica, Linn., 

 the small Conmion Domestic Fly, the larva of which lives in moist manure. 



^arcophaga, IMeig., differs from Musca, by the eyes being wide apart in both sexes ; the eggs in some species 

 are hatched within the abdomen of the parent, as is the case with ^1/, caniaria, Linn, [a very abundant species], 

 which is larger and longer than the Meat Fly : the female deposits her young larvse upon flesh, carcases, and 

 sometimes in the wounds of persons. 



We terminate the Creophila; by some subgenera contrasting with the preceding in the form of the head, situation 

 of the wings, or of their external cells. 



Ac/lias, Fabr., remarkable for the horn-like elongations of the sides of the head ; with the antennae inserted high 

 in the forehead. 

 Idia, Meig., has the front of the head produced into a beak. 



The two following have the terminal cells of the wings extending to the posterior edge ; the abdomen is 

 flattened. 

 Lisjje, Latr., has the body oblong ; the antenna; nearly as long as the face ; and the style plumose. 

 Argijritis, Latr., has the body short ; the abdomen very tlat, nearly semicircular ; the head short and broad ; the 

 antennae very short ; with the seta elbowed. 



In all the remaining Muscides, the alulets are small, or nearly obsolete ; the balancers exposed ; and 

 the principal nerves of the wings extending to the outer edge of the wings, which closes the posterior 

 cells. 



A second general division of the Muscides, that of tlie .\NTiioMyziDES, is composed of species liaving 



