DIPTERA. 621 



Ceroplattts, Bosc, has the palpi apparently composed of a single joint, and the antennae fusiform and compressed. 

 Our last general division of the Tipulaires, is the T.forales, consisting of species having the an- 

 tenna; scarcely longer than the head in both sexes, thick, and 8- or 10-jointed, forming a perfoliated 

 mass ; nearly cylindric in the majority, but fusiform in others, or terminated by a large joint ; the body 

 is short and thick ; the head is generally almost entirely occupied by the eyes in the males. From the 

 nervures of the wings and palpi, these Diptera approach the Tipulaires fungivores. 



Cordyla, Meiff., differs from all the rest in having 12-jointed antennae ; the eyes are round, entire, and apart, and 

 the ocelli wanting ; the le^s are long-, and spiny at the tips of the tibiae. The others have ll-jointed antenna, and 

 the eyes of the males very larg-e. 



SimuUttm, Latr. (Culex, Linn.), has no ocelli, and the eyes of the females are internally notched, and crescent- 

 shaped. The species are very small, frequenting damp places, and are very troublesome, from their biting, or 

 rather pricking the flesh ; they also sometimes penetrate into the generative parts of cattle, and kill them. Like 

 gome of the Culicidae, they are also called Musquitoes. 



In the others, there are three ocelli. 



Scatopse, Geoff., approaches the last in having the eyes emarginate, but differs from all in having the palpi very 

 small, and apparently composed of but a single joint. T. latritiarum, De Geer, a small fly, commonly found in 

 privies. 



Penfhetria, Meig., has the eyes entire, and separate in the two sexes ; the legs are long, and not spinose. 



Bilophiis, Meig. {Hirtaa, Fabr.), has the eyes contiguous in the males, often occupying almost the whole of the 

 head ; the tips of the tibiae have a coronet of spines. 



Bibio, Geoff. {Hirtcea, Fabr.), has 9-jointed antennae, forming a perfoliated mass. The species are very sluggish, 

 flying but little. Some of them are very common in gardens ; the two sexes often differ greatly in appearance and 

 colours. Tip. hortvlana, Linn. Their larvae live in dung, earth, and manure, and have small rows of spurs on the 

 segments of the body. The pupae are not inclosed in cocoons. 



Aspistes, Hoffm., has only 8-jointed antennae ; the last joint forming an ovoid mass. 



All the following Diptera (a very small number excepted), have the antennae composed [at first sight] 

 of only three joints, the first of which is sometimes so short, that it is scarcely to he reckoned as such ; 

 the last is in many transversely annulated, but without distinct separations. It is often accompanied 

 by a seta, generally lateral, or placed at the top of the joint in others ; having at its base one or two 

 joints, and sometimes simple, sometimes hairy. If this seta is terminal, it happens in many that its 

 length diminishes and its thickness increases, forming a kind of style. Although this style is, 

 in effect, a continuation of the antenna;, it would create confusion in the nomenclature by adding the 

 number of its joints to that of the ordinary joints of the antennae. The palpi have never more than tw o 

 joints. Some of these (a small number excepted) cast their larva-skin on becoming pupae, and have 

 the sucker composed of six or four pieces ; the proboscis, or at least its lips, is always exserted ; the 

 palpi, when present, are external, and inserted near the margins of the oral cavities, and the sucker arises 

 near this cavity. The larva, in those which retain the larva skin, serves as a cocoon for the pupa, 

 without changing its primitive form. This subdivision comprises three families, \_Tanystoma, Nota- 

 cant ha, and Athericera']. 



THE SECOND FAMILY OF THE DIPTERA,— 

 The Tanystoma, — 

 Is distinguished by having the last joint of the antennae (not reckoning the style), not transversely 

 annulated, and the sucker consists of four pieces. 



Their larvae resemble long worms, nearly cylindric, and without feet, with a scaly head of constant 

 form, always furnished with hooks or retractile appendages, which serve them for gnawing or sucking 

 the substances on which they subsist. The majority live in the earth, and change their skin on 

 assuming the pupa state. The pupae are naked, and exhibit many of the external parts of the imago, 

 which escapes from its exuviae by a slit down the back. 



A first division comprises those Diptera which have the proboscis always entirely, or almost entirelv, 

 exserted, with the sheath of a rather solid, nearly horny consistence, being more or less porrected, 

 and either cylindric, conic, or filiform, terminating without any marked dilatation ; the palpi 

 are small. 



Some of these live by rapine, and have the body oblong, with the thorax narrow in front ; the wings 

 incumbent on the body ; the proboscis short, or but slightly elongated, and forming a kind of beak ; 

 the antennae are close together, and the palpi exposed. 



