LIMNOBINA ANOMALA. 101 



Whether the absence of spurs at the tip of the tibia?, which 

 distinguishes all the known genera of Limnobina anomala* is an 

 indication of some degree of relationship, is as yet uncertain. 

 Until future discoveries disclose the hidden links of relationship 

 between these genera, we can perceive a distinct connection 

 between three genera only, Rhamphidia, Elephantomyia, and 

 Toxorrhina, which I have, for this reason, united in the subsec- 

 tion Rhamphidina, treated separately at the end of this para- 

 graph. The genera Dicranoptycha, Orimarga, Elliptera, and 

 Antocha show a certain obscure relationship to each other, especi- 

 ally in the venation. Atarba and Teucholabis seem to be isolated 

 forms. A character worthy of notice in several genera belonging 

 to the Limnobina anomala is the tendency of the veins near the 

 costa to coalesce with each other. The first and second veins 

 are very closely approximated in Elliptera and Dicranoptycha ; 

 in Antocha the first longitudinal vein coalesces very early with 

 the costa, and in Toxorrhina the second vein seems to be entirely 

 absorbed by the first ; the latter portion of the first is coalescent 

 with the costa. A similar coalescence is observable in Styrin- 

 gomyia. In the present state of our knowledge we cannot judge 

 yet of the importance of these analogies. 



Eleven genera constitute this group at present ; three of which 

 belong to the subsection Rhamphidina. Of the remaining eight 

 genera two {Dicranoptycha and Antocha) are common to Europe 

 and to North America ; three have been found as yet only in 

 Europe {Orimarga, Elliptera, TJiaumasloptera) ; two only in 

 America {Teucholabis and Atarba), and one is found included 

 in amber and copal {Styringomyia). 



Subsection RHAMPHIDINA. 



One submarginal cell (none in Toxorrhina) ; four posterior cells ; a discal 

 cell; no marginal cross-vein ; normal number of antennal joints sixteen 

 (through the coalescence of the basal joints of the flagellum, 15 or 12). 

 Tibise without spurs at the tip. Ungues smooth on the under side. 

 Empodia indistinct or none. Rostrum conspicuously prolonged. 



The absence of any vestige of a marginal cross-vein, however 

 unimportant it may appear as a character, acquires its significance 

 by its constancy and its concomitance, in the three genera, with 



1 Except perhaps Atarba, about which I am in doubt. 



