SUBDIVISION OF THE ATHERICERA. 375 



boscis ; but it is in Syrphus, Milesia, and Cheilosia, that 

 })erhaps the most elegant species occur : and Baccha, 

 lastly, is remarkable for its lengthy and slender body. 



{336.^ The third general subdivision consists of 

 the DicH^T^ — the characters of which are to have two 

 setse to the proboscis ; the antennae usually patelliform, 

 with a dorsal seta, or tuberculiform. In these insects, 

 also, we find a gradual obliteration of the nervures of 

 the wings, which speedily become considerably reduced 

 in quantity. These form two families — the Athericera 

 and the Pupipara ; the first of which is distinguished 

 by the sucking tube being contained within the pro- 

 boscis, and the terminal joint of the antennae usually 

 patelliform. These are subdivided into eight tribes ; — 

 1. The Scenopinidce ; 2. The CephalopsidcB ; 3. The Lon- 

 chopteridce; 4. The PlatypezidcB j 5. The Conopsidce j 

 6. The Myopidce; 7 -The (Estrida; and, 8. The Muscidee. 

 The first six of these tribes have but little connecting 

 affinity, and seem to associate themselves here, from no 

 other situation more conveniently offering to receive 

 them. The first exhibits the remarkable combination of 

 a generally inferior organisation, in intimate union with 

 wings of complicated structure. The insects, consti- 

 tuting but one genus, occur usually in the windows 

 of houses. The second tribe, the Ccphalopsidm, are 

 minute insects with large heads, which are nearly all 

 eye ; they are found in meadows and upon low shrubs, 

 and but rarely frequent flowers. The third, or Loncho- 

 pteridce, are also very difficult to locate : of these there 

 is but one genus which presents the singularity of a 

 sexual disparity in the neuration of the wings, — a 

 structure found in the Diptera but rarely, as it occurs 

 besides, only in Penthetria among the Tipulce. The 

 present insects occur among herbage, in marshy situ- 

 ations. The fourth, or PlatypezidcB, are distinguished by 

 their posterior tarsi being imbricated obliquely. They 

 are rare insects, and are probably fungivorous. The 

 fifth, or ConopsidcB, appear to borrow their structure 

 from the superior and inferior groups : thus, by their 



B B 4 



