628 INSECTA. 



the third joint shorter, nearly ovoid, and the fourth joint shorter, the style not terminal, but dorsal. O. Ily- 

 poleon, Fab. 



Nemotelus, Geoff., differs from the preceding in having- the proboscis long, siphon-shaped, elbowed at the 

 base, and lodged in a frontal protuberance of the head, like a beak. 



, In the others the third joint of the antenna? forms, with the preceding, an ovoid or globular mass, terminated 

 by a long seta. The scutellum is rarely spined. 



ChrysocMora, Latr. (Sargus, Fab.), has the third joint of the antenna; conic, and terminated by a seta. 



Sargus, Fab., has the same joint subovoid, or nearly globose, rounded, or obtuse at the tip, with the seta dorsal. 

 The first joint is nearly cylindrical ; the scutellum rarely spined ; the body often elongate, green, or coppery, and 

 fcrilUant. Musca cupraria, Linn., a very common species, the larva of which resides in cow dung, and is of an 

 oval, oblong form, narrowed and pointed in front, with a scaly head furnished with two hooks. It becomes a pupa 

 beneath its own skin, and without materially altering its form. 



Vappo, Latr. (Pachygaster, Meig.), differs chiefly from Sargus in the antenna? being shorter, with the basal joints 

 transverse. 



Our second general division of those Diptera which have a sucker received in the prohoscis, 

 or sheath, and the antennae only 2- or 3-jointed, comprises those which have the proboscis 

 generally membranous, bilabiate, long, elbowed, and bearing two palpi implanted a little 

 above the elbow, and most commonly received into the oral cavity, and has only two pieces 

 in the sucker, when it is always protruded. The last joint of the antenna;, always furnished 

 with a style or seta, has no annular division. The palpi are hidden in repose. This division 

 forms 



THE FIFTH FAMILY OF THE DIPTERA,— 



The Athericera, — 



The proboscis of which is generally terminated by two large lips ; the sucker has never more than 

 four, and often only two pieces. The larvae have the body very soft, contractile, annulated, narrower 

 in front, with the head of a variable figure, and its external organs consisting of one or two hooks, 

 accompanied in some genera with fleshy lobes, and probably in all with a sort of tongue destined to 

 receive the nutritive fluids. The spiracles are four in number; two placed in the prothorax, and two 

 at the extremity of the body, on scaly plates ; each of the latter is formed, in many, of three small 

 spiracles close together. These larvae do not change their skins ; that which they first possess hardens, 

 and becomes a kind of cocoon for the pupa. It also shortens, and assumes an oval form ; the anterior 

 part, which was slenderest in the larva, thickens. We also discover in it traces of articulation, and 

 often vestiges of spiracles, although they no longer serve for respiration. [The manner in which the 

 transformation to the pupa state is effected, is described in the general observations on the order, and 

 need not be repeated.] 



Few of the Athericera are carnivorous in the perfect state. They are found, for the most part, on 

 flowers, leaves, and sometimes on human excrement. 



This family comprises the genera Conops, (Estrus, and the major part of that of Musca, of 

 Linnaeus. 



We naturally commence with those species of the latter genus, which have the sucker formed of 

 four pieces and not of two, as in all the other Athericera. They form a first tribe, Svrphid^e. 



The proboscis is always long, membranous, elbowed near the base, terminated by two large lips, and 



the sucker inclosed in an upper canal ; the upper piece of the sucker is thick, and notched at the tip, 



tire others are slender ; to each of the two labial ones, representing maxillae, is attached a small, 



slender palpus ; the head is hemispherical, and occupied for the most part by the eyes, especially in 



the males. Its anterior extremity is mostly produced like a muzzle, or beak, receiving the proboscis 



when it is folded in inaction. Many species resemble Humble-bees, and others Wasps. This tribe 



comprises but a single genus, 



Syrphus, — 



A first general division of which is composed of those with the proboscis shorter than the head and thorax. 



Some of these have the front of the head produced into an eminence above the oral cavity ; at the head of 

 these are placed such as have the seta of the antennae plumose ; the body short and hairy, resembling Humble-bees. 



Volucella, Geoffr., has the third joint of the antennas oblong, its outline forming a curvilinear and elongate 

 triangle. 



Musca mystacea, Linn-., a very common species, the larva of which lives in the nests of Bombi, its body being 



