BY FREDERICK A. A. SKUSE. 71 



This section awaits definition. The above enumerated charac- 

 ters derived from Baron Osten-Sacken's comparative survey of 

 this section and the Tipulina, will be found to distinguish the 

 majority of the genera. But the genus now described under the 

 name Clytocosinus, though exhibiting all the striking features of 

 the section, differs in possessing a long, straight, glabrous rostrum, 

 destitute of a nasus, and agrees with the Tipulina in the position 

 of the anterior branch of the second longitudinal vein. 



Baron Osten-Sacken omitted Macqu art's Ctenogyna in his 

 synopsis of the desci-ibed C^ewop/iorce (Studies I. , p. 166), and with 

 the assistance of only incomplete information about the insect 

 evidently seemed inclined (I.e. p. 177-178) to regard it as a near 

 relative of Ptilogyna. Macquart's figure of the head is misleading, 

 as it does not show the nasus. 



Synopsis op Genera. 



I. Antennce branched in ^ only. 



(J antennae with alternate long and short branches ; the 

 long ones not much longer than the short ; ^ antennse not 

 much longer than the head. Dictenidia, Brulle. 



2 antennse as long as the thorax ; joints cylindrical, 

 decreasing in length from the third to twelfth ; third very 

 long. Xiphura, Brulle. 



Antennse longer than the head ; ^ antennne with alternate 

 long and short branches, the long ones sometimes much longer 

 than the short ; twelfth joint with only one pair of branches. 

 Adminiculum conspicuous. Ctenophorra, Meig. 



^ antennse with four equally long branches on the same 

 joint ; the twelfth joint with two pairs of branches. Admini- 

 culum wanting. Pselliophora, O.-Sack. 



II. Antennce not branched in either sex. 



Antennse considerably longer than the head, serrate ; third 

 and following joints slender at the base and enlarged into a 

 broad knob towards the underside. Prionota, v. d. Wulp. 



