13 <! 



46 DIPTERA OP NORTH AMERICA. [PART IV. 



Section II. Limnobina anomala. 



'Rostrum conspicuously prolonged, at least as long as the head, some- 

 times nearly as long as the whole body ; no marginal cross-vein 

 (Subsection Rhamphidina) . 14 



Rostrum shorter than the head. 16 



Wings without submarginal cell ; Tab. I, fig. 6. 



Gen. VIII. Toxorrhina. 

 Wings with a submarginal cell. 15 



Rostrum not much longer than the head. Gen. VI. Rhamphidia. 



15 { Rostrum not much shorter than the whole body. 



Gen. VII. Elephantomtia. 

 ( Discal cell open. 17 



( Discal cell closed. 19 



' Second basal 'cell considerably shorter than the first, the great cross- 

 vein being placed about the middle of the wing. 18 

 Second basal cell of about the same length with the first, the great 

 cross-vein being in its usual position ; Tab. I, fig. 1l 



Gen. XI. Elliptera. 

 fThe discal cell being open, is coalescent with the second posterior 

 | cell; Tab. I, fig. 9. Gen. X. Orimarga. 



1 The discal cell being open, is coalescent with the third posterior cell. 



Gen. XV. Thaumastoptera. 

 C No vestige of a marginal cross-vein ; Tab. I, fig. 13. 



19 \ • Gen. XIII. Atarba. 

 ' Marginal cross- vein extant (although sometimes weakly marked). 20 

 C The first longitudinal vein ends in the costa nearly opposite the inner 



end of the submarginal cell, or very little beyond it. 21 



20 \ The first longitudinal vein ends in the costa very far beyond the inner 



end of the submarginal cell, the distance being about equal to 

 t the breadth of the wing ; Tab. I, fig. 8. Gen. IX. Dicranoptycha. 

 ( Submarginal cell as long or but little longer than the first posterior 



cell : Tab. I, fig. 12 Gen. XIV. Teucholabis. 



j Submarginal cell much longer than the first posterior cell ; Tab. I, 



fig. 11. Gen. XII. Antocha. 



17 



Section III. Eriopterina. 



Wings present. 23 



( No wings. Gen. XIX. Chionea. 



( Five posterior cells. Gen. XXVI. Cladura. 



( Four posterior cells. 24 



/ The inner marginal cell has the shape of an almost equilateral tri- 

 24 J angle ; Tab. II, fig. 11. Gen. XXV. Ceyptolabis. 



' The inner marginal cell has the usual elongated shape. 25 



