12 BULLETIN 1218, TJ. S. DEPARTMENT OF AGRICULTURE. 



horse. During the feeding four droplets of clear fluid exuded from 

 the anus. After feeding she again brushed the labellum with the 

 forelegs and tried to fly. Her abdomen appeared to be fully dis- 

 tended with blood. This species was never observed among the stock 

 much earlier than 4 a. m. or later than 5 p. m. It was most abundant 

 and active between 10 a. m. and 3 p. m. 



Both males and females of this species in captivity were very 

 fond of sweets. They fed eagerly on after-dinner mints and on 

 sugar solution. 



Mating And Egg Development. 



No mating of Tab anus punctifer was observed. The reared fe- 

 male No. 128 which emerged August 21 and which fed on the host 

 on August 26 was then placed in an aquarium cage with several 

 reared males. On September 4 the female was found dead lying 

 on top of the soil in the cage. A T. punctifer larva was devouring 

 the contents of her abdomen, which contained egg masses partly 

 developed. 



OVT POSITION. 



No oviposition of this species was obtained in captivity. Egg 

 masses were easily found in nature. They are attached to bulrush 

 stems, coarse grasses, trunks of small trees (fig. 9; PI. I, C) which 

 grow in or hang over water, and occasionally to overhanging tim- 

 bers of irrigation boxes. The distance of the eggs above the water 

 varies from 1 to 3 feet. 



Prof. A. C. Burrill reports one observation made in Idaho of 

 Tabanus punctifer depositing a mass of eggs during " a hot August 

 day, on the second strand of a barbed-wire fence midway between 

 two posts and within 3 feet of water in the irrigation ditch parallel 

 to the fence." 



The senior author, on August 9, 1918, observed a female (No. 

 T693) of this species which had just finished ovipositing and was 

 still in position, head downward. She was engaged in brushing 

 the end of the abdomen over the mass, apparently distributing 

 the cement with which the mass of this species is usually covered. 

 The fly was not frightened away at the approach of the observer. 

 The stem upon which she was resting was broken oif and she was 

 watched at close range for some little time before she flew away. 



The egg masses were found most abundantly during August 

 around the shore of Alkali Lake (fig. 9). 



Egg Mass. 



The egg mass of Tabanus punctifer (PL I, C) varies considerably 

 in shape and size, depending upon the dimensions of the surface to 

 which it is attached. When this surface is wide and flat the 

 perimeter of the base of the mass is somewhat elliptical in shape, 

 about 15 millimeters long and 10 millimeters wide. A mass attached 

 to a slender object has a much narrower base. The eggs (fig. 10, a) 

 are arranged in from three to five layers parallel to the base of the 

 mass. Each layer has a perimeter slightly smaller than the layer 

 preceding it, so that the mass has a pyramidal appearance. One 

 mass of three layers measured 5 millimeters in thickness. Relative 



