PROC. ENT. SOC. WASH., VOL. 20, NO. 9, DEC., 1918 189 



contrary, however, as the group is differentiated into a remark- 

 ably large number of species. The larvae of most of them live 

 in water or wet soil, and the adults are found in greatest abund- 

 ance in well-watered situations. In collecting them advantage is 

 taken of certain characteristic habits. The collector himself 

 attracts the blood-thirsty females of most species of deer flies 

 (Chrysops) and of a few kinds of horse flies (Tabanus), and as 

 they circle about his head they fall easy victims to the net. Deer 

 flies at times are attracted to flowers, the males frequently, as is 

 the case also with the species of Pangonia; hence, looking over 

 flowers must not be omitted by the collector of species of this 

 family. Their favorite flowers in this region so far as known, are 

 chinquapin, Ceanothus, and dogbane. 



Inspecting horses and cattle is naturally the most important 

 method of finding horse-flies and it is good also for certain deer 

 flies. Sometimes, numerous species are caught in a short time 

 about farm stock. Horse-flies like to sun themselves on fences 

 and poles; and often sit on roads, particularly about puddles. 

 A few species are only obtained, and a number of others, may be 

 caught, by sweeping vegetation about wet places. Most of the 

 horse flies are active and alert and are strong fliers, so that their 

 capture is by no means easy. In fact collecting them appeals 

 to one as rather a sporting proposition with the odds generally 

 in favor of the flies. On a hot summer day one frequently is re- 

 minded of his impotence by hearing the characteristic buzz of a 

 horse-fly', which usually darts by so swiftly it is not seen, turns 

 and goes off as rapidly as it came. 



The returns for collecting Tabanidae are remarkable consider- 

 ing the large size of most of the species. It was surprising indeed 

 to get a brand new genus in so well collected a vicinity as that of 

 the District of Columbia. Some of the species are either rare, 

 local, or very hard to obtain, as the paucity of records for them 

 shows. Knowledge of these forms can be increased and probably 

 numerous species can be added to our list by assiduous and in- 

 telligent collecting. We trust that publication of the list and 

 especially of the keys will stimulate collectors to improve our 

 knowledge of the Washington Tabanidae. 



The total number of species in the list is 54. The standard of 

 comparison of local lists, in the Eastern United States, is the New 

 Jersey list of Professor C. W. Johnson. 2 It contains 74 species of 

 Tabanidae. New Jersey has an unusual variety of environments 

 suitable to horse flies, having the maritime, pine-barren, ordinary 

 lowland and upland swamps, bogs, and watercourses, and so 



2 " The Insects of New Jersey," Ann. Hop., N. J. State Mus. 1909-1910, 

 pp. 738-742. 



