56 Psyche [April 
the outer cross-band nearly as in typical schwarzii. The latter 
individual measures fully two mm. ‘The base of its wings is less 
hyaline, but otherwise the wings are as described. The first ventral 
segment of the abdomen is only dusky, not white. The third specimen 
mentioned in the Biologia is in the Wheeler collection at the American 
Museum. ‘This species corresponds to eacisa Loew of the European 
fauna, 
Tachydromia varipennis Coquillett. 
Coquillett, Proce. Ent. Soe. Wash., v. 266 (1903). 
Slosson, Ent. News, xiv. 266 (1903) habits. 
Length 2mm. Shining black, pro- and metapleurae pruinose, coxae, base 
of femora and proximal part of tarsifuscous. Outer antennal joint short ovate, 
the terminal arista three times the length of the antenna. Palpi whitish. 
Humeri constricted from the central part of the thorax by an evident groove; 
no bristles on dise of notum, scutellar bristles minute. Hypopygium minute, 
terminal, without conspicuous hairs. Halteres white. Wings infumated, 
the base, tip and a transverse streak in the middle, but not including the mar- 
ginal and submarginal cells hyaline. 
I have four specimens from the type lot, received from Mrs. Annie 
Trumbull Slosson. ‘They were taken in the White Mountains at 
Franconia, New Hampshire. The type is in the National Museum, 
number 6774. It is this species that is mentioned in Aldrich’s Cata- 
logue, page 314 under schwarzii, as occurring in New Hampshire. 
In her article, Hunting Empids, in the October issue of the Ento- 
mological News for 1903, Mrs. Slosson gives the following notes on the 
habits of this fly. ‘‘About the first of July I always find here a pretty 
little creature running rapidly over wet stones at the margin of streams. 
It is a tiny fly with gray wings variegated with black, and its habits 
are odd and interesting. ‘Though its wings are fully formed and quite 
‘apable of flight, it very rarely uses them. When pursued by the 
collector it runs swiftly like an ant on and around the stone, and will 
continue this elusive performance for many minutes, though by spread- 
ing its pretty wings it could at once escape capture. Only in desperate 
extremity, as a very last resort, will it sometimes take flight and rest 
upon another near-by stone. For a long time I found them very 
difficult to catch. But at last I discovered that by seizing the stone 
on which one was running and dropping it quickly into my net I had 
the little fellow safe and sound.” 
