198 PROCEEDINGS OF THE ACADEMY OF 



part of my task was in my purpose only a secondary one. I wanted to publish 

 new American genera and species ; in order to establish the former I found it 

 necessary to give more precise definitions to already existing genera ; I hope 

 these definitions will hold good ; but the grouping of these old and new genera 

 according to their natural affinities is the task of a monograpbist ; it requires 

 a study of the family in its totality, embracing the species from all parts of 

 the world ; what I have given in this respect is nothing but a temporary ar- 

 rangement, adopted here, because an arrangement of some kind was required. 



It would have been the task of a monographist, for instance, to define more 

 precisely the subdivision of the family of the Tipulidce terricolce in two tribes, 

 those with short, and tho=e with long palpi. This subdivision (first adopted by 

 Latreille in 1805, in the 14th volume of his Histoire naturelle des crustaces etdes 

 insectes, ) although excellent, is not sufficient, since there are intermediate forms 

 which it does not embrace ; the character itself, on which it is founded, cannot 

 stand alone ; in order to be made available, it must be supported by charac- 

 ters taken from other organs. (Among the Tipulidce with short palpi there are 

 some, like Pedicia, Amalopis, Arrhenica, etc., having the last joint 

 of the palpi much longer than the preceding, and showing in this way an ap- 

 proach to the tribe with long palpi.) 



Not pretending to write a monograph, I do not define more accurately the 

 group which forms the subject of the present paper ; I took it, as defined by 

 former authors, and I could do so the more readily as I have not met with any 

 form of doubtful position. 



Without entering into a detailed historical account of the generic and other 

 subdivisions established and subsequently given up by different authors within 

 the group in question, I will advert only to Macquart's attempt to subdivide 

 the genus Limnobia Meig., as it is the most important for my purpose. 



Macquart separated from Limnobia Meig., all species with a petiolate areolet, 

 and formed of them the genus Limnophila. Now, a more natural subdivision, 

 as will be shown below, is that founded, not on the presence or the absence of 

 the petiolated areolet, but on the presence or absence of the second radial area. 

 Nevertheless, Macquart's subdivision was very near the true one, because all 

 Limnobia? with one radial area are at the same time destitute of a petiolate 

 areolet, and most of those with tiro radial area? possess this areolet. I say 

 most of them, because there are a few species of Limnobias iciih two radial 

 arece and no petiolate areolet, and these species were most unnaturally united 

 by Macquart with the Limnobice with one cubital area. (The European Lim- 

 nobia sylvatica Meig., for instance, is one of them ; in Macquart's Histoire 

 naturelle des dipt/ res it is to be found in the genus Limnob ia Macq., to- 

 gether with L. modest a, morio, etc) This was the fault of his subdiv- 

 sion. 



in a paper published by me in the Stettiner entomologische Zeitung in 1854, 

 I have suggested that the presence of the second radial area, combined with 

 characters taken from the structure of the genital organs, lead to a more 

 natural subdivision. The classification, adopted in the present paper, is the 

 development of this suggestion. 



The bulk of the tribe Tipulce ivith short palpi, may be divided in two sections, 

 showing the contrast of characters expressed in the following two columns : 



* Limnobia {Pedicia) albivitta Wk., L. {Pedicia) contermina Wk., L. c inct i- 

 pes Say, ten uipe s Say, r o strata Say, ma cr oc era Say, a r gu s Say, fas c i p en- 

 nis Say, humeralis Say, gracilis Wied., cario?iaria Macq,,badia Walk., 

 biterminata Wk., i g n o b i 1 i s Wk s i m u 1 a n s Wife., t u r p i s IH\, p r o m i n e n s 

 Wk., {Rhamphidia ?), Symplecta c a n a Walk., Rhamphidia f 1 a v i p e s Macquart, Lim- 

 nobiorynchus canadensis VVestwood, Anisomera longicornis Walk., Erioptera 

 calopt era Say, and the European E. fascipennis Zctt. I omit the species from 

 the West Indies and Mexico ; I omit also Trichocera, no species of this genus having 

 been described by me here. The names printed in italics are those of species which 

 have been identified by me; the others are as yet unknown or doubtful. 



[Aug. 



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