42 ORTHOBlillAPHA. 



Discal cell nearly always present, but absent in some genera of 



EmPID.E, DoLICIIOPID^. PLATTPBZIDyE, etC. 



" In all cases of doubt as to whether a fly belongs to the 

 Beachyckea or Nematooeba (and doubt could only arise in some 

 8tratiomyim; and Leptid.e), because of an anuulated, flagellum- 

 like 3rd joint at the anteunaj (as in Rhacliicerus, Beris, Xi/Iophagus, 

 Coenomyki; etc.), the contraction of the anal cell towards the 

 wmg-margin provides an infallible character." (Yerrall, 1909.) 



" Larva) with parallel jaws, moving upwards and downwards, 

 or outwards and downwards, ^^hich are used for piercing, 

 hacking, boring or sucking. Head not fully developed, only 

 a jaw-case \\ithout ganglia present, which, however, sometimes 

 is almost a head, because of the outwardly projecting eyes. 

 Chain of ganglia beginning behind the jaw-case. Larvae with 

 rudimentary mouth-parts ; meta- or amphi-pueustic, and com- 

 posed of 10 to 12 segments." (Brauer.) 



Tahles of Families in Nematocera. 



1. Thorax with a conspicuous V"Shaped 



suture on the niesonotum (indistiuct 

 but present in Ptychopteuin^ie). 

 Discal cell normally present. All the 

 veins equally distinct and complete . . Tipulidae, p. 265. 

 Thorax without a conspicuous V" 

 shaped suture on the niesonotum 

 (except in incomplete form in some 

 Blepharocebid^). Discal cell al- 

 ways absent, except in Rhyphid^ . . 2. 



2. Wing with seven longitudinal veins 



(apart from the forkings of any of 

 these) reaching the margin of the 

 wing. Auxiliary vein always present. 3. 

 Wing with less than seven longitudinal 

 veins (apart from the forkings of any 

 of these) reaching the margin of the 

 wing (except in C'hirono7>iiis, in which 

 the auxiliary vein and 2nd lougi- 

 tudinal vein are always faint) 6. 



3. Wings bare, never with scales or hairs. 



Eyes rounded. Proboscis never formed 



for biting ; palpi incurved 4. 



Wings never bare, always thicklv 

 covered with scales or hair, or both. 

 Eyes reuiform (kidney-shaped). Pro- 

 boscis nearly always expressly formed 

 for biting, or at least capable of doing 

 so ; palpi in Culicid^ stift" and 

 straight 5. 



4. Discal cell always present. Head in 



male holoptic (eyes contiguous), or 

 practically so. Antennae distinctly 

 jointed, the joints annular or oval . . Rhyphidae, p. 549. 



