100 DIPTERA OF NORTH AMERICA. [PART IV. 



Section II. LIMNOBINA ANOMALA. 



One submarginal cell ; normal number of the antennal joints sixteen. 



This group is meant to be an artificial one, and for this reason 

 I do not add anything to its short character. The brevipalpous 

 Tipulidse with a single submarginal cell and the antennae of 

 which, at the same time, count 16 joints, never fail to show, as 

 far as hitherto observed, very striking peculiarities of structure, 

 requiring their separation from the very compact and natural 

 section of the true Limnobina with fourteen-jointed antennas. 



Thus the genera Dicranoptycha, Orimarga, Atarba, Teuclio- 

 labis, and Styringomyia have distinct empodia ; a character 

 altogether foreign to the Limnobina ; moreover, each of these 

 genera possesses characters in the venation, in the structure of 

 the forceps of the male or of the antennae, which abundantly 

 justify its separation from the Limnobina. 



Bhamphidia, Toxorrhina, Elephaniomyia, Antocha, LUiptera, 

 and Thaumastoptera have no distinct empodia ; nevertheless, their 

 structural peculiarities are such, that the expediency of their sepa- 

 ration from the Limnobina will not be disputed. 



The link connecting these genera is purely artificial ; but ex- 

 perience has proved that the establishment of this group, proposed 

 by me in 1859, is very useful in the system, by collecting under 

 one head a number of genera which would not find a fitting 

 position in any other section. The genera belonging here have 

 but a very limited number of species ; most of them are com- 

 paratively rare, and, for this reason, as yet little known. Large 

 additions to this group are therefore to be still expected, and 

 these additions may develop links of relationship, not suspected 

 now, as much between already known genera, as even with some 

 of the other sections of the Tipulidse brevipalpi. 



