VI 



PACK 



Suborder Cyclorrhapha 175 



Division Acroptera 175 



Division Aschiza 175 



Division Schizophora 176 



Characters of the pupae 177 



Suborder Orthorrhapha 177 



Division Nematocera 177 



Division Bracliycera 178 



Suborder Cyclorrhapha 178 



Divisions Acroptera, Ascliiza, and Schizophora 178 



Keys to suborders: — 



Larvas 179 



Pupas 179 



Imagines 180 



Suborder Orthorrhapha 180 



Keys to divisions: — 



Larvee 180 



Pupae 180 



Imagines 181 



Division Nematocera 182 



Tabular arrangement of families 182 



Keys to families: — 



Larvae 183 



Pupae 185 



Imagines 188 



Tribe Polyneura 190 



Tipuloidea 190 



Tipulidce 191 



Keys to subfamilies 193 



Ctenophorinae 194 



Tipulinse 195 



Principal papers on North American Tipulidaj 206 



Limnobiidae 207 



Keys to subfamilies 208 



Cylindrotominae 210 



Limnobiinge 212 



Pediciinge 216 



Limnophilinae 220 



Rhamphidiinae 226 



Eriopterin^ 227 



Hexatominae 232 



Trichocerinae 234 



Papers on the Biology of North American Limnobiidae 238 



Ptychopteridae 238 



Rhyphidse 241 



