40 CROP PEST COMMISSION OF 



most important from an economic standpoint, for it is very persistent 

 in its attacks upon stock. It habitually alights on the under parts of 

 animals, where they have difficulty in reaching it, and it is therefore 

 almost sure to satisfy its appetite before leaving. However, all three 

 of these species are important stock pests. They fly at the same time 

 and in the same places and are often mistaken for one and the same 

 insect. They flew around the laboratory building in great numbers 

 ^nd could be seen renting on the siding and windows at almost any 

 time during the day. If the screens were allowed to stand open they 

 entered the building in numbers and eventually collected on the win- 

 dows, where they died of starvation. 



The three species just considered all have stripes on each side 

 of the abdomen, while the three following species have rows of rounded 

 spots on each side of the abdomen. 



FIG. 19. Little horsefly (Tabanus pumilus). female, en- 

 larged to three diameters. 



TABANUS PUMILUS Macquart (Little Horsefly). This is one of 

 the smallest species of its genus, being only about one-third of an 

 inch in length. Thorax black, with narrow gray stripes. Narrow 

 gray posterior border of each abdominal segment expanded into a 

 very small triangle at the middle; thus the abdomen has a median 

 row of small gray triangles, and on either side of this a row of small 

 gray spots. Wings hyaline. One specimen taken at Leesville, April 

 28, 1905 (Newell). This species is also distributed over the eastern 

 United States. 



TABANUS SAGAX Osten Sacken. Femora blackish; thorax uni- 

 formly yellowish, without stripes; wings narrowly yellowish on the 

 anterior margin, otherwise hyaline; abdomen with a rather prominent 

 median dorsal band and a row of rounded spots on either side. On'v 

 half inch in length, some specimens larger. This species has been 

 taken at several places in the eastern United States. Captured in 

 Louisiana at the following places: Shreveport, June 14 (Newell); 

 Frierson, July 14; Logansport, September 6 (Garrett). 



