I' 
636 INSECTA. 
Platystoma, Meig., differs in having the head more compressed transversely, so that the upper surface is more • 
slanting, and the antenn* appear inserted in the middle of the face. * 
This naturally conducts us to Timia, Wied., and Mosillus, belonging to the next division. 
The eighth division, Gymnomyzides, is composed of small Muscides, with a short body, curved, 
nearly glabrous, of a shining black colour, the head much compressed transversely, as in Platystoma, 
without any inferior prominence ; the scutellum advanced ; the abdomen short, depressed, and some- 
times terminated by a small point, and the legs nearly glabrous. 
Celyphus, Dalm. (having the scutellum extended over the body), and 
Lauxania, Latr. (with the scutellum of ordinary size and the seta plumose), have the antennae longer than the 
head. The others have them shorter. 1 
In some of these they are very short and wide apart, and lodged in impressed fossulae, the space between them : 
being elevated. \ 
Mosilhis, Latr., has the first cell of the posterior edge of the wings almost closed ; Meigen divides them into two | 
subgenera, — Timia, with the abdomen 6-jointed, and Ulidia, with it 5-jointed. " 
Homalura, Meig., with the abdomen 5-jointed, and ; 
Act(M'a, Meig., with it 6-jointed, have the first cells of the posterior limb of the wings entirely open and ; 
longitudinal. 
In others the antennae are nearly contiguous, and the cells of the posterior edge of the wing are always open. j 
Gymnomyza, Fall., has the antennae inserted beneath a sort of arch, and near the middle of the face. 
Lonchcea, Meig., has them inserted higher, without any appearance of an arch. j 
The second section of the Muscides, and which forms our ninth and last sub-tribe, the Hypocera, ! 
consists of a single subgenus, distinct from all the preceding in many respects. The palpi are always < 
external ; the antennae inserted near the oral cavity, very short, terminated by a large globular joint, 
with a very long seta ; the wings have only three oblique discoidal nerves, whence the name Trinmra 
given to them by Meigen ; the legs are very short and spiny, with the thighs large and compressed, 
especially in the hind legs. They are extremely active, and form the genus Phora, Latr. ; Tri- 
neura, Meig. 
Our second general section of the Dipterous insects differs from the preceding in the 
mouth, antennae, and transformations, and other less important characters ; whence Dr. Leach 
was induced to form them into a distinct order, Omaloptera. Those which terminate this 
section have a certain relation with the hexapod wingless insects, composing our order of 
Parasites, or the genus Pediculus of Linnaeus. I 
This section forms | 
THE SIXTH FAMILY OF THE DIPTERA,— j 
The Pupipara (or the Nymphipara of Reaumur). J 
The head of these insects, seen from above, is divided into tw o principal portions, the posterior 
being the principal, supporting the eyes and receiving the anterior part in an emargination in front. 
This is also divided into two parts, the posterior being the largest, and supporting the antennae at its 
sides ; and the other constitutes the mouth organs. The inferior and oral cavity of the head is occu- Ij 
pied merely by membrane, out of the extremity of which the sucker protrudes, arising from a small ■ 
bulb, or advanced peduncle, composed of two setae close together, and covered by two coriaceous, ! 
narrow, elongate and villose plates, which act as sheaths. Whether these valves represent, as I pre- j 
sume, the palpi of other Diptera, or whether they are pieces of a sheath properly so called, as regarded 
by M. Dufour, who has discovered two small bodies, which he takes for palpi ; it is not less certain ^ 
that the proboscis of these insects differs materially from that of the preceding Diptera, and that the j 
proboscis has in this case more resemblance to that of the Fleas, 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 labrum ; 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 leathery-like skin. The head is more i 
intimately united to the thorax than in the preceding families. The antennae, always situated at the ^ 
lateral and anterior extremity of the head, appear either under the form of a tubercle bearing three 
setae, or that of small hairy plates. The size of the eyes varies, being very small in some species. In 
