10 DIPTERA OP NORTH AMERICA. 



but among the Tipulidce. The abnormal structure of the thorax 

 in the wingless genus Chionea is less surprising, its form depending 

 chiefly on the situation and size of the alary muscles, and, however 

 it may differ in some respects from all the other genera of Tipu- 

 lidce, it would be still more inconveniently located in any other 

 family. Whether the genus POLYMERA Wied., which is distin- 

 guished by its moniliform antennae and the basal cells not reaching 

 to the middle of the wings, may be placed among the Tipulidce, 

 appears doubtful. I should have thought it belonged to the tribe 

 Psychodidce, had not Macquart figured the thorax of Polymera 

 fusca with a distinct V-shaped transverse suture. 



The variety of forms prevailing in the family of Tipulidce has 

 caused t*he foundation of a rather large number of genera. In. 

 order to facilitate the description of the new species and the iden- 

 tification of the described ones, a considerable increase of the 

 number of genera is indispensable. 



On the whole, the Tipulidce may be divided into two sections, 

 the TIPULINA having long, and the LIMNOBINA having short palpi. 

 This division, indeed, is no natural one, since some genera with 

 long palpi agree in all the rest of their organization more with the 

 genera of the second than of the first section. 



The genera of Tipulidce hitherto established, as I know them by 

 sight, or, in part, by the definitions of their authors, may be dis- 

 tributed as follows. To the Tipulina belong: TIPULA Linn., 

 PRIONOCERA Loew, PACHYRHINA Macq., NEPHROTOMA.^^., CTE- 

 NOPHORA Meig., DOLICHOPEZA Meig., OZODICERA Macq., CTENOGYNA 

 Macq., GYNOPLISTIA Westw., PTILOGYNA Westw., MEGISTOCERA 

 Wied., APEILESIS Macq., PTYCHOPTERA Meig., MACROCHILE Loew, 

 PROTOPLASA 0. S., PTEROCOSMUS Walk., HESPERINUS Walk., BIT- 

 TACOMORPHA Westw., and RHAMPHIDIA Meig. To the section of 

 Limnobina must be referred : LIMNOBIA Meig., GLOCHINA Meig., 

 RHIPIDIA Meig., GERANOMYIA Hal. (= Aporosa Macq.), DICRA- 

 NOMYIA Sleph., ANTOCHA 0. S., ELEPHANTOMYIA 0. S., LIMNOBIO- 

 RHYNCHUS Westw. (= ToxorMna Loew), DICRANOPTYCHA 0. S., 

 TEUCHOLABIS 0. S., ERIOPTERA Meig., SYMPLECTA Meig. , CRYPTO- 



LABIS 0. S., GoNOMYIA^J/ey., GNOPHOMYIA 0. S., CLADURA 0. S., 



TRICHOCERA Meig., CYLINDROTOMA Meig., ANISOMERA Meig., AR- 

 RHENICA 0. S., ERIOCERA Macq., DICRANOTA Zett., ULA Hal, 

 AMALOPIS Hal., TRICYPHONA Zett., EVANIOPTERA Guer., PEDICIA 

 Latr., LIMNOPHILA Macq., EPIPHRAGMA 0. S., DICRANOPHRAGMA 



