223 Indian Museum Notes. [Vol. Vf, 



The injury to the horse from the larvae may take four forms, (i) 

 The attachment to the walls of the stomach causes an irritation 

 which may interfere with the normal action of the glands or reduce 

 the extent of glandular surface ; (2) the bots abstract some nutri. 

 ment from the walls of the stomach, or by absorption, from the con- 

 tents of the stomach itself ; (3) by collecting, particularly in the 

 region of the pylorus, they serve as an obstruction to the free 

 passage of food from the stomach to intestines ; (4) in passage through 

 intestines they may attach themselves at times to walls or in rectum 

 and cause great irritation. Some consider this as the source of 

 most of the serious symptoms from presence of bots. In any of 

 these methods the extent of injury depends in large degree upon 

 the number of bots present, a few probably causing no appreciable 

 damage, while large numbers (sufficient as we have seen them, to 

 completely cover large patches of the stomach walls) must cause 

 serious disturbance and loss of nutrition and would seem a sufficient 

 cause to produce fatal results. From the nature of the case no 

 definite statistics can be given for the losses incurred. It is 

 probably safe to say that nine-tenths of all colts and horses that 

 are pastured during summer, and a smaller proportion of driving an 

 work horses, become infested with bots each year. Aside from the 

 injuries inflicted by the larvae, we must consider the excitement 

 produced by the flies when depositing the eggs as a source of loss 

 and this in many cases is by no means insignificant. 



Life-history and habits. — Adults of this species are about three- 

 fourths of an inch in length, the wings are transparent with dark 

 spots, those near the centre forming an irregular, transverse band. 

 The body is very hairy, the head brown with whitish front, thorax 

 brown, abdomen brown, with three rows of blackish spots, which are 

 subject to considerable variations. In the females the segments are 

 often almost entirely brown with simply a marginal series of yellowish 

 spots, while in males the abdomen may be almost entirely yellow or 

 very light brown, with brown or dark spots very distinct. The males 

 are rarely seen, for while it is one of the most common occurrences 

 to witness the female around the horses depositing their eggs, the 

 males evidently hold aloof. They are readily distinguished by the 

 form of the abdomen, which lacks the two tubular segments at the 

 end, and is provided on the under-side of the last segment with a 

 pair of dark brown or black hooks, or clasping organs. Otherwise 

 except the colour of the abdomen, already mentioned, they resemble 

 very closely the females. The eggs are light yellow in colour and will 

 be found attached to the hairs of the shoulders, forelegs, under-side 

 of body, and sometimes even the mane and other parts of the body, 



