254 AMERICAN DIPTERA. 



ANOTHER FOSSIL. XEMESTRIXID 'FL,Y . 



BY T. D. A. COCKERELL. 



Neraestrinidse must have been comparatively abundant in Colo- 

 rado in Miocene times. The Florissant shales have already pro- 

 duced three species ; it now becomes necessary to add a fourth : 



Hirnioneiira occultator n. sp. 



9. Length (excluding ovipositor) 14 mm.; head, thorax and 

 abdomen black ; abdomen not banded, 8 mm. long and 6 wide, but 

 its excessive breadth partly due to compression ; ovipositor a little 

 over 2 mm. long, slender, very strongly curved, its structure evi- 

 dently as in Rhynchocephalus ; wings lOJ mm. long, hyaline, 

 faintly dusky, the base and costal region dilute reddish , veins 

 brown ; eyes bare, facets about 30 /a across. No proboscis visible ; 

 what looks like a stout proboscis, extending about 2 mm. beyond 

 head, is a fragment of some plant. 



Venation nearly as in the living ff. texana Ckll., but with these 

 differences : 



(1) The long or middle radio-medial cross-nervnre does not reach 

 the base of the first posterior cell, but falls a moderate distance short 

 of it, about as in H. vulcauica. (On the other hand, the base of 

 the third submarginal cell, between the forks of the media, is 

 pointed as in Rhynchocephalus volaticus, not truncate as in H. 

 vulcanica. ) 



(2) The base of the fourth posterior cell is more obtuse, but it 

 and the adjacent nervures are otherwise similar. The narrow base 

 of this cell, with three nervures leaving it (upwards, downwards 

 and inwards) at practically the same point, is as in H. texana, but 

 very different from H. vulcauica and especially H. melanderi. 



(3) The second posterior cell is shifted downwards, so that its 

 base is only half contiguous with the apex of the fourth. 



The cells between the branches of the media and cubitus are 

 somewhat narrowed apically, but open. 

 The abdomen, as usual, is hairy. 

 IZa6.— Miocene shales of Florissant, Station 14 {8. A. Rohwer). 



