DIPTERA. 625 
The male organs in some are accompanied by plate-like appendages. 
Orthochile, Latr., has the proboscis forming a small beak. 
In the rest the proboscis is short, or scarcely prominent. 
Dolichopus proper, has the third joint of the antennae nearly triangular, but little elongated, with a seta of 
moderate length, without a thickened knot between the middle and extremity. 
These insects are often of green or copper colours; the legs are long, and very delicate. They station them- 
selves on walls, the trunks of trees, leaves, &c. Some run with celerity on the surface of water. The male organs 
of generation are always external, large, complicated, and folded beneath the abdomen. D. ungulatus, Fab., the 
larva of which lives in the earth : it is long, cylindric, with two points in form of two recurved hooks. The pupa 
has two curved horns in front of the thorax. 
Sybistroma, Meig., has the last joint of the antennae nearly in the form of the blade of a knife, with a very long 
seta, knotted beyond the middle. 
The male organs in the others are furnished with filiform appendages. In some the hind part of the antennae is 
either oval, triangular, or very long. 
Rhaphium, Meig., has it very long, and nearly lanceolate. 
Porphyrops, Meig., has it hatchet-shaped or triangular, with a villose seta, the first joint of which is indistinct. 
Medeterus, Fisch., has the seta simple and dorsal, with the basal joint distinct and elongated, and the last joint 
of the antennae oval. 
Hydrophorus, Macq., differs from Medeterus in having the seta entirely terminal. 
In the others, the third joint of the antennae is nearly globose, and the seta always villose. 
Chrysotus, has it terminal. 
Psiloptis, has it inserted rather above. 
Diaphorus, has it inserted lower, and the head nearly spherical, and entirely occupied by the eyes, in the males, 
thus appearing to conduct us to the next family, Platypezinte, The wings, ocelli, and other characters derived 
from the parts of the head, corroborate those which we have mentioned, but it is impossible for us to enter into 
such details. 
The Platypezinae of Meigen, from which Macqiiart has judiciously removed the genus Cyrtoma, and 
to which we have added that of Scenopinus, and his family Megacephali, is composed of Diptera very 
similar in the proboscis, antennae, and wings to Dolichopus, but the body is depressed, with the head 
hemispherical, and almost entirely occupied by the eyes, at least in the males. The legs are short, 
without spines, and with the posterior tarsi often flat and broad. 
These Diptera are very small. Some of them have a seta in the last joint of the antennae. Those 
in which it is terminal, and the eyes contiguous above in the males, form two subgenera. 
Callomyia, Meig., has the basal joint alone of the posterior tarsi dilated, but as long as all the rest united. 
Platypeza, Meig., has the four basal joints of the posterior tarsi flattened. 
Pipunculus, Latr., {Cephalops, Fall.), has the seta inserted on the back of the third joint, near its base ; the 
tarsi are not dilated, the eyes not united above in either sex, and the head nearly globose. 
Scenopinus, Latr., has no seta to the terminal joint of the antennae, which is narrower and longer than in the 
preceding. 
THE THIRD FAMILY OF THE DIPTERA,— 
The Tabanides, — 
Has, for its characters, a proboscis exserted, and generally terminated by two lips ; with the palpi 
porrected, the last joint of the antennae annulated, and a sucker of three pieces. It comprises the 
genus 
Tabanus, Linn., — 
And is composed of large flies, well known for the tox'ments they inflict upon horses and cows, of 
which they pierce the skin, in order to suck their blood. The body is generally but slightly hairy; 
the head is as wide as the thorax, nearly hemispherical, and covered, except in a narrow space, particu- 
larly in the males, by the eyes, which are generally golden-green, with purple stripes. The antennae 
are nearly as long as the head, 3-jointed ; the last joint being terminated in a point without seta or 
style at the tip, often notched at the base above, wdth transverse divisions, in number from three to 
seven. The proboscis in the greater number is nearly membranous, perpendicular, of the length of 
the head or rather shorter, nearly cylindrical, and terminated by two elongated lips ; the two palpi 
mostly rest upon it, and are thick, villose, conical, compressed, and 2-jointed ; the sucker, inclosed in 
the proboscis, is composed of six pieces like lancets, and which from their number and respective situ- 
ation represent the parts of the mouth of the Coleoptera. [It is only the females which possess this 
number of lancets ; the mouth of the males is much weaker, and has only four. This sex is harmless, 
s s 
