DIl'TERA, 381 



two lips, and accompanied by palpi. The antenna;, except in the last 

 subgenus or Phora, have always appeared to be inserted near the 

 front. The larvae 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 all 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 Omaloptera. 

 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 Pedicuhis of Lin- 

 naeus. 



The second section will form our last family of the Diptera. 



FAMILY VI. 



PUPIPARA. 



These Insects, at least the Hippoboscae, where distinguished by 

 Reaumur, under the analogous appellation of Nymphipara. 



Their head, viewed from above, is divided into two distinct areje 

 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, tlie pos- 

 terior large and coriaceous, bearing the antennae 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 setae, and covered 

 by tAVO coriaceous, narrow, elongated, and pilose laminae which form 

 its sheath. Whether these laminae or valvulae 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 laminae 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 cover the base of the pro- 

 boscis of the Flea. 



