106 THE EEPORT OF THE No. 36 



Then there is another with a light yellow body, about the size of the female hot, 

 which 1 imagined was the male hot; it also has a pair of mandibles, but they are frailer 

 than those on the nose fly. 



Now we get to the heel fly, which belongs to the same family and is the largest 

 of the family that I know. It is about the size and shape of a small honey bee and 

 carries the heaviest set of mandibles of any of the stock bee family; it is also the 

 poorest flier; it hovers around in the grass or near the ground on calm, hot days, and 

 darts up, striking the cattle on the first place it reaches, generally from the heels up 

 to the hocks and sometimes on the rump; then up goes the animal's tail and it bolts. 

 If there is a four wire fence in front of the animal it goes right on through, while the 

 fly calmly drops to the grass and sails along until it comes to the next cow or steer, 

 which also throws up its tail and has business elsewhere. By that time all the cattle 

 have taken the hint and disappeared. 



Another one I captured near the horses one day about as large as the heel fly and 

 the same color; the only difference I noted was that its mandibles were jet black and 

 very strong, while all the rest were brown. One thing I noticed with all of these insects 

 Is that they are always worse on hot, calm days and are very weak fliers, never appear- 

 ing when there is any wind, excepting the hot which is with us all summer. 



A correspondent (No. 7) from Chatham, Ont., writes: — 



i 



I think your correspondents of July 28th and September 1st are in error about 

 what they call nose flies, as the flies do not strike on the horse's nose but underneath, 

 just back of the opening of the jawbone. I have caught scores of them by placing 

 my hand beneath the horse's chin. They do not deposit eggs, as they are males of the 

 common bot fly. The eggs that are on the lips were not deposited there, but adhered 

 when the horse was rubbing his legs, as the horse does not use the tongue for that 

 purpose. The difference in colour of eggs can be accounted for in this way. When 

 first deposited they are yellow, but turn darker until hatched; then the shells which 

 still adhere to the hairs get quite light. 



2. Waeble Flies. 



For the last two or three years reports have reached us from Chateauguay 

 and Huntingdon Counties that certain flies were very troublesome on the dairy 

 herds in pasture during June and early July. It was asserted that they stung 

 the cattle and chased them about the fields. This summer a specimen of the 

 pest was sent me, and on comparing it with type specimens of Warble flies sent me 

 Iby Dr. Hadwen, of British Columbia, I identified it as Eypoderma hovis. Dr. 

 Hewitt, to whom I submitted the specimen, corroborated my identification. 



The explanation of this outbreak of dovis in the Chateauguay-Huntingdon 

 district is clear when it is known that a large importation of cattle from Scotland 

 has occurred annually for many years. The breeders of this district admit that 

 warbles on the backs of the cattle are more common now than they were a few 

 years ago. 



Following is a table which may be of service in identifying the common 

 genera and species of the Oestridse. 



Oestbidae. 



(Bot Flies.) 



Common genera and species: 



a. Costal vein ends at tip of R4_|-5; Ml-f2 is straight, not reaching the margin, 



and cell R5 wide open; squamae small, arista bare; ovipositor elongate. 



Cktstrophilus. 

 6. Wings with spots and smoky median cross band. G. equi (horse bot fly). 

 66. Wings without spots. 

 c. Posterior cross-veins (M-Cu) beyond the anterior cross-vein (R-M); legs blackish 



brown. O. hcemorrhoidalis (red-tailed bot fly). 



