ZOOL.— Vol. III.] KELLOGG— NET-WINGED MIDGES. 219 



the family over the world has already been indicated in the 

 Introduction and in the discussion of the classification of 

 the genera. Although so few species are known, three 

 continents are included in the range of the family, these 

 conditions suggesting that we have to do with a family 

 probably formerly including numerous species scattered 

 over the world, but now dying 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 

 Blepharocerids are recorded. The larvae and pup£e live 

 shallowly submerged only in swiftly running, clear, fresh 

 water; such conditions are provided by all, or nearly all, 

 mountain or hill brooks and hardly anywhere else. As the 

 known species extend from the equator to subarctic latitudes, 

 temperature or climate offer probably no barriers, nor 

 probably does altitude, the North American species ranging 

 from nearly sea-level (Blepharocera ca-pitata) to 8,000 feet 

 (Bibiocephala elegantuliis) . 



In their local distribution those Blepharocerid species of 

 which we know anything at all nearly sufficient for speaking 

 with confidence, offer certain strikingly contrasting condi- 

 tions. Blepharocera ca-pitata, for example, specimens of 

 which come from Ithaca, New York, from Ampersand 

 Creek in the Adirondacks, and from Riviere des Chiens, a 

 brook flowing into the St. Lawrence about twenty miles 

 east of Quebec, and which has been taken in three or four 

 other localities in northeastern United States and Canada, 

 is common in three streams. Coy Glen, Six Mile Creek, 

 and Cascadilla Creek, near Ithaca, New York. But there 

 are at least a dozen other streams similarly swift, clear, and 

 with smooth rock beds, within a radius of fifteen miles of 

 Ithaca, and in most of these Professor Comstock and his 

 students or the writer have looked for the species in vain. 

 On the other hand, Bibiocefhala comstocki, B. doanei, and 

 Blepharocerajordani,^rB,\.io\xnd by the writer in Los Gatos 

 and Campbell creeks, near Stanford University, have since 



(3) February 9, 1903. 



