114 APPENDIX. 



sub-transparent, with slightly blackish tinge, but with no spots 

 or markings other than the veins. The flies first appear in May 

 (in Virginia), and remain until "right cold weather." They at- 

 tack the cattle in the fields, probably never penetrating the sta- 

 bles (Railliet). 



When on the cattle and sucking the blood, the wings are slightly ele- 

 vated and are held out from the body, not at right angles, but approach- 

 ing it approximately an angle of 60 from the abdomen. The legs 

 are spread out widely, and the beak inserted beneath the skin of the 

 animal, and is held in nearly a perpendicular position. . . . The 

 fly, before inserting its beak, has worked its way through the hairs, clo^e 

 to the skin. While feeding, however, the hairs, which can be seen over 

 its body, do not seem to interfere with its speedy night when alarmed; 

 for at a fling of the tail, or an impatient turn of the head, the flies rise 

 instantly in a cloud for a foot or two, returning again as quickly and 

 resuming their former positions. ._ 



When the flies are abundant, the characteristic habit of clus- 

 tering about the bases of the horns is indulged in. They do no 

 damage at all to the horns ; the popular notions that the fly eats 

 into the substance of the horns, causes them to rot, and lays eggs 

 in them from which maggots hatch which penetrate into the brain, 

 are all without foundation of fact. The flies congregate on the 

 horns solely for rest in a place where they may be undisturbed. 

 The resting position of the flies differs from the sucking position, 

 in that while on the horn the wings are held nearly flat down the 

 back, overlapping at base, and diverging only moderately at tip. 

 The beak is held in a nearly horizontal position, and the legs are 

 not widely spread. 



When feeding, the flies are found over the back and flanks and on 

 the legs. During a rain storm, they flock beneath the belly. When the 

 animal is lying down, a favorite place of attack seems to be under the 

 thigh and back belly, around the bag. On the horns, the flies form 

 clusters entirely around the horn for a space of two inches from the 

 base; they seem to prefer the concave to the convex side of the horn. 



The eggs are laid by the flies in freshly-dropped dung, in the 

 day-time, and are laid singly, never in clusters. The larvae issue 

 within twenty-four hours after the eggs have been laid, and de- 

 scend into the dung, not very deep. The larvae are dirty-white 

 maggots, not more than one-third of an inch long. The larvse 

 become fully grown in about . five days, and descend into the 

 ground below the dung from a half to three-quarters of an inch 

 to pupate. The adult flies issue from the puparise in about one 



