DIPTEKA. 5 



the lower and anterior part of tlie head. Labium ending in a thicker 

 bilobed piece (the "labella"), traversed internally by radiating tracheae; 

 sheathing the mandibles and maxilhx) when these are developed. La- . 

 b7'um closing this sheath above, embracing the lingua. Palpi attached 

 to the base of the maxillae, or, if these are wanting, seated on the prop 

 of the proboscis. Prothorax very small, immovably joined to the meso- 

 thorax, which is the largest piece. Wings and halteres developed, 

 almost always. Abdomen at the base much more slender than the 

 tliorax, its dorsal segments at least distinct (4 or more). Legs of 

 each pair close together, and the posterior two pau's to each other ; the 

 fore pair usually farther from the intermediate. Ungues and onychia 

 symmetrical pairs. 



PROBOSCIDEA. 

 with distinct joints, at least 6, 



(usually more than 10) ... 1. Nemocera. 



Lwith 3 to 10 joints; after 

 the 3d closely united, or 

 abruptly slighter. Pos- fbranched or inter- 

 terior veins of the wing \ laced, more or less 2. Brachycera. 



Lsimple, detached, 

 and veiy faint . 3. Hypocera. 





Nemocera, Latr.; Macq.; &c. 

 Antenna} articulis discretis saltern sex saepius decem et idtra. 

 Palpi plerumque deflexi, articulis pluribus exsertis. 

 Areola analis in margiuem posteriorem aperta. 



Add. Antennae plerumque capite longiores, graciles, iiliformes aut 

 setaceee. 

 Alidae scuteUares obsoletae ; 

 Lobus axdlaris quoque ut plurimum. 

 K\cc venis multimodis, nee facile in typum redigendis. 

 Ocelli ssepe desvuit. 

 Ungues hand raro denticulati. 



Brachycera, Macq. 

 Antennas articulis post tertium connatis, vel extremis (1-3) nimis 



attenuatis. 

 Palpi porrecti, aut proboscidi iucunibcutes, quasi exarticulati. 

 Areola analis ferme clausa. 

 Venai posteriores ramosae vel anastomosi connexae. 



Figure usually stouter and more compact than in Nemocera, and the 

 head broader, and more vertical. Cavity of the mouth at the underside 



