636 INSECTA. 



Platjixtoma, Woip;., dilTcrs in liaving; the liea J movf compressod transversely, so tliat the upper surface is more 

 slanting-, and llie antenn;e appear inserted in the middle of the face. 

 This naturally conducts us to Timia, Wied., and Mun'dln^, beluiiging; to the next division. 



The cii^htli division, Gymnomyzides, is composed of small Muficides, with a short Ijorly, curved, 

 nearly glabrous, of a sliining black colour, the head much compressed transversely, as in Platystoma, 

 without any inferior proraiuence ; the scutellum advanced ; the abdomen short, depressed, and some- 

 thnes terminated by a small point, and the legs nearly glabrous. 



Cchiphus, Dalin. (having- the scutellum extended over the body), and 



Laiij iiiiia^ Lati'. {\\ tth the scutellum of ordinary size and the seta plumose), have tlie antenna; long-er than the 

 head. The others h;ive them sliorter. 



In some of these they aie very short and wide apart, and lodg-ed in impressed fossuh-e, the space between them 

 beim; elevated. 



Mu-siUns, Latr., has the first cell of the posterior edLreof the ^vingfs almost closed ; ^Meigen divides them into two 

 sul)i::enera. — Tiinia, witli the abdomen 6-jointefl, and Ulidia, with it 5-jointed. 



Iloinnhirn, Meig., with the aliilonien S-jointed, and 



Actora, I\]ci-., with it 6-juinted, ]ia\'e the first cells of the posterior limb of the win^s entirely open aiid 

 longitudinal. 



In othrrs the antennae are nearly contiguous, and the cells of the posterior edg;e of the wing; are always open. 



Giimiioiniizii, Fall , has tlie antenna? inserted beneatli a sort of arch, and near the middle of the face. 



Luncluca. .Meiir., lias them inserted higher, witliout any appearance of an arch. 



The second section of the Muscides, and which forms our ninth and la^t sub-tril)c, tlie IIyc'OCERa, 

 consists of a single subgenus, distinct from all the preceding in many respects. The palpi are always 

 external ; the antenna; inserted near the oral cavity, very short, termiiiateil by a large globular joint, 

 with a VL-rv long seta ; tlie wings have only three oblique discoidal nerves, vvhence the name Trmeura 

 given to them hv Meigen ; tlie legs are very short and spiny, with the thighs large an(i comiiressed, 

 c^l)eeiallv in the hind legs. Tliey are extremely active, and form the genus Phora, Latr. ; Tri- 

 neura, ^leig. 



Our second general section of the Dipterous insects differs from the preceding in the 

 mouth, antennae, and transforuiatiuns, and other less important clutracters ; whence Dr. Leach 

 was uiduccd to form them into a distinct order, 0/naIoptcra. Those winch tenmnate this 

 section have a certain relation with the hexapod wingless insects, composing our order of 

 Parasites, or the genus Fe die alas of Liunojus. 



This section forms 



THE SIXTH FAMILY OF THE DIPTEIU,— 



Ti-iE Pupii'ARA (or the Ni/iaphi/jara of Reaumur). 



The head of these insects, seen from above, is divided into two principal portions, the posterior 

 being the principal, supporting the eyes and receiving the anterior part in an emargination in front. 

 This is also dividnl into two parts, the posterior being the largest, and supporting the antenna; at its 

 sl(h:s ; and the other constitutes the mouth organs. The inferior and oral cavity of the head is occu- 

 pied merely l)y nn'hiluane, out of the extremity of Avhich the sucker protrudes, arising from a small 

 bulb, or ad\'anccd peduncle, composed of two seta^ close together, and covered by two coriaceous, 

 narrow, elongate and villose plates, which act as sheaths. AVhether these valves represent, as 1 pre- 

 sume, the palpi of other Dipiera, or whether they are ]>ieces of a sheath properly so called, as regarded 

 by iM. Dufour, who lias di.scnverrd two small bodies, which he takes for palpi; it is not less certain 

 that tlic prouoscis of these insects differs materially from lliat of the preceding Diptera, and that the 

 I'roboseis has in this case more resemblance to that of the Flea^, from which it is, however, removed 

 by the absence of articulations. In Melophagus the base of the plates of the sucker is covered by two 

 small, coriaceous, triangular pieces, united, and forming a kind of lahrum ; they seem to represent, in a 

 small degree, the two pieces which cover the base of the rostrum of the Flea. 



The body is short, broad, flat, and defended by a solid or leathcry-hke skin. The head is more 

 intimately uniteil to the thorax than in the preceding families. The antenna?, always situated at the 

 lateral and anterior extremity of the bead, appear either under the form of a tubercle bearing three 

 seta3, or that of small hairy jilatcs. The size of the eyes varies, being very small in some species. In 



