THE CANADIAN ENTOMOLOGIST 159 



A FOSSIL FUNGUS-GNAT. 



BY T. D. A. COCKERELL, BOULDER, COLORADO. ' 



Some time ago Miss Olive M. Braden collected a number of 

 fossils in the Miocene shales of Florissant, Colorado, and through 

 the kindness of Mr. A. E. Holch, of the Cripple Creek High School, 

 I was enabled to examine the series and identify the species. Miss 

 Braden very kindly gave to the University of Colorado Museum 

 several species new to our collection, the most interesting being a 

 fungus-gnat, described below. It is remarkable to find such fragile 

 insects excellently preserved, and to note that they are entirely 

 of the same type, in many instances, as their modern representatives. 

 In a million years or so, some of the Mycetophilidae appear to have 

 remained without evolutionary progress, except to the extent of 

 slightly modifying or shifting minor specific characters. 



Mycetophila bradenae, n. sp. 



Length about 6 mm.; general appearance and structure 

 exactly as in the living M. punctata Meigen, but anterior tibial 

 spurs longer. Antennae cylindrical about L5 mm. long, joints 

 about as broad as long; wings brownish, not spotted, venation quite 

 normal for the genus; abdomen with alternating light and dark 

 bands; hind tibiae with two rows of long dark spines, as in M. 

 punctata, about 320 microns long; anterior tibiae about 990 microns 

 long, with spur 660. The following wing measurements are in 

 microns: End of subcosta (on radius) to origin of radial sector, 

 660; length of radio-medial cross-vein, 225; branching of cubitus 

 basad of level of lower end of radio-medial cross-vein, 160; branching 

 of media from lower end of radio-medial cross-vein, 145. 



This is the first genuine Mycetophila found fossil in America. 

 Scudder's M. occultata, from White River, Colorado, is said to have 

 the legs unarmed, and not very long, and the venation cannot be 

 clearly made out. It is evidently not a true Mycetophila. In 

 Europe Mycetophila is known by a number of species from Baltic 

 Amber, of Oligocene age. 



May, 1915 



