PTYCHOPTERA. 309 



c 



Section VIII. PTYCHOPTERINA. 



Only a single longitudinal vein posterior to the fifth vein ; two submarginal 

 cells. Labium largely developed ; palpi long. Tibiae with spurs at the 

 tip. Thoracic suture deeply sinuate. 



The five known genera of this section form two distinct groups, 

 distinguished by the following characters : — 



1. No subcostal cross-vein ; first submarginal cell much longer 

 than the second ; three or four posterior cells ; collare obsolete ; 

 a peculiar, small spatulate, membranaceous, ciliated organ at the 

 foot of the halteres : Ptychoptera, Bittacomoiyha. 



2. A subcostal cross-vein is present ; the second submarginal 

 cell is much longer than the first ; the number of posterior cells 

 is raised to six, in consequence of the presence of a supernumerary 

 longitudinal vein in the first posterior cell ; collare large : Froto- 

 pjasa, Tanyderus, Macrochile.^ 



Ptychoptera alone occurs in Europe : it is common to that 

 continent and to America; Bittacomorpha and Protoplasa have 

 been found in North America only ; Tariyderus in South Ame- 

 rica ; Macrochile is included in the Prussian amber. 



This section is the most aberrant of all the Tipididse. The 

 venation shows peculiarities not found elsewhere ; the large de- 

 velopment of the labium, the prolonged epistoraa, the deeply 

 sinuate thoracic suture, etc., separate the Ptydiopterina entirely 

 from the rest of the family, and the latter character may be in- 

 dicative of a relationship to the Blepjharoceridae. 



Gen. XLIV. PTYCHOPTERA. 



Two submarginal cells, the first much longer than the second ; no sub- 

 costal cross-vein ; no discal cell ; four posterior cells, the second very 

 short ; only a single longitudinal vein after the fifth vein (Tab. II, fig. 19, 



' I do not know about the collare of Macrochile. 



