ZooL.— Vol. III.] KELLOGG— NET-WINGED MIDGES. 211 



Imaginal Genitalia (PL XXII, figs. 2, 3, 4, 5, 6, 7 and 8). 

 The modifications of the last segments of the abdomen with 

 their processes are marked in the different Blepharocerid 

 species examined, and if known for all the species so far 

 described could without doubt be advantageously used in 

 specific, perhaps generic diagnoses. It is in the male that 

 the more complex development of these parts, which may 

 be called the external genitalia, takes place, and in which 

 most difference is apparent in a comparison of species. Of 

 the species whose genitalia the writer has examined, viz., 

 Blepharocera ca-pitata, B. joj'datii diud B. osten-sackeni, and 

 Bibiocephala elegantulus, B. doanei and B. comstocki, 

 Blepkarocera capitata (PI. XXII, figs. 2, 3, 4, 5 and 6) 

 presents the simplest type of male genitalia, Sind. Bibiocephala 

 snowi (PL XXII, figs, 7 and 8) the most complicated. The 

 figures make the structure of these parts in the two species 

 noted so obvious that a detailed description of them is 

 unnecessary. 



The other species may be grouped roughly between these 

 two extremes, each species showing, however, its own 

 characteristic modifications. In the female, the modifica- 

 tions of the segments and development of epiphyses are less 

 marked, as shown in PL XXII, figs. 4, 6 and 7. The typical 

 condition is manifest in all the species examined. The single 

 pair of epiphyses and both the dorsal and ventral surface of 

 the last abdominal segment bear special sense papillae, per- 

 haps of simple tactile function. The structure of these papillae 

 with their special nerve endings is shown in PI. XXII, fig. 5. 



V. Habits of Larv^, Pup^, and Imagines. 



LarvcB. — The larvae of all the Blepharoceridse yet known 

 live submerged in swift-running, clear streams, which 

 practically limits their occurrence to mountainous or at least 

 hilly regions. They are found usually in groups of lesser 

 or greater number in favorable spots, sometimes, as in the 

 case of Ble-pharocera capitata, in Coy Glen, near Ithaca, 

 New York, forming "patches" of hundreds of individuals 



