DIPTERA. 381 
two lips, and accompanied by palpi. The antenne, except in the last 
subgenus or Phora, have always appeared to be inserted near the 
front. The larve of these Diptera, although susceptible of being 
hatched in the venter of the mother, live abroad and feed on various 
substances, vegetable or animal. These Insects have formed our 
first general section, which is divided into five families. Those of 
the second differ in ail these respects and in some others that are less 
general, and this dissimilarity has even induced Doctor Leach to 
form the latter into a particular order, or that of OmAnoprera. 
Those which terminate it, and which are destitute of wings and 
halteres, have a certain affinity with the Hexapoda and Aptera that 
compose our order of the Parisita or the genus Pediculus of Lin- 
neeus. 
The second section will form our last family of the Diptera. 
FAMILY VI. 
PUPIPARA. 
These Insects, at least the Hippobosce, where distinguished by 
Reaumur, under the analogous appellation of Nymphipara. 
Their head, viewed from above, is divided into two distinct arez 
or parts. One posterior, and more particularly composing the head, 
gives origin to the eyes and receives the other part in an anterior 
emargination. The latter is also divided into two portions, the pos- 
terior large and coriaceous, bearing the antenne on its sides, and the 
other constituting the apparatus of manducation. The inferior and 
oral cavity of the head is occupied by a membrane; from its ex- 
tremity issues a sucker arising from a little bulb or projecting pedicle, 
composed of two closely approximated threads or sete, and covered 
by two coriaceous, narrow, elongated, and pilose lamine which form 
its sheath. Whether these laminz or valvulee represent (as I pre- 
sume) the palpi of other Diptera, or whether they be parts of a true 
sheath, as is the opinion of M. Dufour in speaking of a species of 
Ornithomyia—Ann. des Sc. Nat., X, 243, XI, 1—where he has dis- 
covered two little bodies which he considers as palpi*, it is not less a 
fact that the proboscis of these Insects evidently differs from that of 
the preceding Diptera, and that the sheath, in this case, would be 
more analogous to the proboscis of the Flea, from which however it 
is removed by the absence of articulations. 
* In the Melophagi, the base of the lamin of the sucker is covered by two little 
coriaceous, triangular, and united pieces, forming a sort of labrum. They seem to 
form a miniature representation of the two pieces that caver the base of the pro- 
hoscis of the Flea, 
