T. D. A. Gockerell—A New Fly. 285 



Art. XXYI. — A New Fly (Fain. Mycetophilidce) from the 

 Green River Beds ; by T. D. A. Cockekell. 



Sackenia gibbosa sp. nov. 



Length fully 6 mm , wings about 4J ; thorax l|- mm long, 

 strongly gibbous in front; head not quite l mm long ; antennse 

 arising about 425 /* above month, and 1530 fi long (the tip may 

 possibly be broken off) ; abdomen • slender, largest about the 

 third and fourth segments ; third and fourth segments each 

 about 620 /u. long ; fifth 680 /a long, sixth 510, seventh 340 ; 

 legs long, covered with minute bristles ; hind tarsi about 



Wing of Sackenia gibbosa. 



2630 fi ; tibial spurs strong, those of hind legs about 340 jjl 

 long. 



Color as preserved brown, the thorax darker than the abdo- 

 men ; wings hyaline, with a cloud on costal margin a little 

 beyond middle, and a small dark spot a little beyond that ; 

 there is a faint indication of a cloud near the end of the basal 

 third of the wing, also in the costal region. 



Measurements of wing in /x. — Auxiliary vein shadowy but 

 quite visible, terminating on the costa about 340 apicad of 

 cross-vein between first and second longitudinal ; cross-vein 

 170 long, its upper end 255 below costa ; distance from cross- 

 vein to end of first longitudinal 2380 ; second longitudinal 

 beyond cross-vein arched, so that at 680 beyond cross-vein it is 

 289 from first, but at end of first it is only 170 from it ; end 

 of second longitudinal to apical point of wing about 425 ; 

 second longitudinal, basad of cross-vein bent downwards, so 

 that at 340 basad it is 255 from first longitudinal ; cross-vein 

 from base of wing 2040 ; first two longitudinals much stronger 

 than the others ; point of junction of fifth and sixth longitudi- 

 nals (viij and vii 2 ) about 340 basad of level of cross-vein ; point 

 of junction of third and fourth (v 1+2 and v 3 ) obliterated, but at 

 935 apicad of cross-vein they are 255 apart, and show no 



