112 



Leptidce, or Snipe-flies 



(c) Mouth parts of Tabanus. After Griin- 

 berg. 



Leptidse or Snipe-Flies 



The family Leptidse is made up of moderate or large sized flies, 

 predaceous in habit. They are sufficiently characterized in the keys 



of Chapter XII. Four blood- 

 sucking species belonging to three 

 genera have been reported. Of 

 these Symphoromyia pachyceras is 

 a western species. Dr. J. C. 

 Bradley, from personal experience, 

 reports it as a vicious biter. 



Oestridse or Bot-flies 



To the family Oestridse belong 

 the bot and warble-flies so fre- 

 quently injurious to animals. 

 The adults are large, or of 

 medium size, heavy bodied, rather 

 hairy, and usually resemble bees in appearance. 



The larvae live parasitically in various parts of the body of mam- 

 mals, such as the stomach (horse bot-fly), the subcutaneous con- 

 nective tissue (warble-fly of cattle) , or the nasal passage (sheep bot- 

 fly or head maggot) . 



There are on record many cases of the occurrence of the larvae 

 of Oestridae as occasional parasites of man. A number of these have 

 been collected and reviewed in a thesis by Mme. Petrovskaia (1910). 

 The majority of them relate to the following species. 



Gastrophilus hamorrhoidalis , the red tailed bot-fly, is one of the 

 species whose larvae are most commonly found in the stomach of the 

 horse. Schoch (1877) cites the case of a woman who suffered from 

 a severe case of chronic catarrh of the stomach, and who vomited, 

 and also passed from the anus, larvae which apparently belonged 

 to this species. Such cases are exceedingly rare but instances of 

 subcutaneous infestation are fairly numerous. In the latter type 

 these larvae are sometimes the cause of the peculiar " creeping myasis. ' ' 

 This is characterized at its beginning by a very painful swelling 

 which gradually migrates, producing a narrow raised line four to 

 twenty-five millimeters broad. When the larva is mature, sometimes 

 after several months, it becomes stationary and a tumor is formed 

 which opens and discharges the larva along with pus and serum. 



