KAM. 1 î I. Ii P 1 1 . \ K ( ) C E K 1 1) . 1 •; 



/ 



North American species one is found in the eastern (AUcghen}-). mountains, two in the middle (Rocky) 

 mountains and six in the western (Sierra Nevada and Coast Range) mountains and two in the West 

 Indies or Mexico. Beside the North American and European species, two species are found in l>ra5;il 

 and one in Ceylon. 



The Blepharoceridae are too unfamiliar to allow us to make any generalizations yet regarding 

 their distribution. Although so few species are known, three continents are included in the range of the 

 family. These conditions suggest that we have to do with a family probabh' formerh- including nume- 

 rous species scattered over the world, but now d3-ing out, a species persisting here and there through the 

 wide range. These persisting species agree remarkably in the habits of the immature stages, and indicate 

 in just what kind of habitat we should look for other members of the family in regions from which as yet 

 no Blepharoceridae are recorded. The great loss of larvae and pupte by the dr3-ing up or contamination 

 of streams and the enormous loss of the issuing flies carried away by the current at the time of emer- 

 gence from the pupa are evidently factors in the peciüiar life of these insects tending to prevent them 

 from holding their own. The larvae and pups live shallowly submerged only in swiftly running, clear, 

 freshwater; such conditions are provided by all, or nearl}- all. mountain or hill brooks and hardly 

 anywhere else. As the known species extend from the Equator to sub Arctic latitudes, temperature or 

 climate offer probably no barriers, nor probably does altitude, the North American species alone ranging 

 from nearly sea-level to Sooo feet above sea-level. 



Desiderata. — There must be several living species of this family yet to be found. In a single 

 summer's attention to the streams in the low mountains near Stanford University, California, the writer 

 was able to add as many species to the North American fauna as had been known before from the 

 whole country. Wherever there are mountains or hills with swift, clear streams one can almost assert 

 that Blepharoceridae will be found. In America the streams of the Ozarks, the Georgia hills, the Tennes- 

 see and North Carolina mountains, the Cascades and Olympics of Puget Sound regions, the Rockies of 

 New Mexico and Arizona and the mountains of Southern California should all be examined. Wherever 

 in the world explorers or collectors are penetrating into mountain regions these insects should be looked 

 for along the streams and cascades. 



With additional species and a widened distribution of old forms known, classification can be 

 revised and more satisfactorily founded. 



The life-history of no Blepharoceridae is fully known; the first eggs of an}- species are yet to be 

 found; the food habits of the males are unknown; a host of observations on the habits are to be made. 



No one has studied the « secondary venation », the creasing of the wings. Are these lines of 

 folding uniform in the species, genus, family? Are there classificatory characters to be derived from 

 them? What is the significance of the little chitinous thickening or knot in the re-entrant angle of the 

 anal margin of the wing? 



Do the well-developed and plainh' differing external genitalia, espedalh- those of males, offer 

 characters which can be used in classification? This is practicallv certain, but as vet no one has even 

 attempted their use. 



Classification. — The nine genera are readil}' separable into two principal groups on the basis 

 of a venational character. The characters drawn from the veins and eves are chiefly depended on to 

 distinguish the genera. 



