'988 Parasitic Insects. 



therefore they become weak and their temperature rises. 

 Kemeny noticed blindness and a bounding heart beat in 2 horses ; 

 the blindness persisted later on. (The gnats also attack the 

 skin of man, especially that of women and children, and infants 

 may die as a result of the stings.) 



The postmortem examination of dead animals shows an 

 edematous infiltration of the subcutaneous or submucous con- 

 nective tissue at the spots corresponding to the swellings, and 

 the sting punctures on the skin or mucous membrane may be 

 recognized as bright red points. Now and then one finds dead 

 gnats in nose, larynx and trachea. The autopsy findings indi- 

 cate death by suffocation ; the spleen is often acutely swollen. 



Apart from housing the animals in dark places, the treat- 

 ment consists in cold compresses or general spongings, also in 

 rub-downs with ammonia, acetate of lead or alcohol; besides 

 carbolized or salicylated oil (10%) or a mixture of lime water 

 and oil may render good service. In case of heart weakness 

 cardiac remedies may be used. Wigand administers i/o to li^ 

 liters of brandy at one^dose, or 14 to y^ a liter at intervals of 

 1 to 2 hours until improvement has occurred. 



Since a radical extermination of the gnats or even a limi- 

 tation of their numbers appears impossible, the safest prophy- 

 lactic measure consists in housing the animals in dark stables 

 at the time of the appearance of the swarms (from April 20 to 

 10-15 of June) and only letting them out to pasture at night. 

 If it is necessary to give the animals their freedom during the 

 day then it is advisable to produce thick clouds of smoke by 

 burning manure or damp weeds, and thus to ward off the gnats 

 from the herd (the production of smoke is also advisable in 

 front of the stable door). Besides, working animals may be 

 smeared on the thin-skinned parts of the body, e. g., around the 

 natural openings, with any stinking mixture, such as inspissated 

 tobacco decoction to which fat and petroleum may be added 

 (Schonbauer), also with assafetida, tar, naphthalin or iodoform, 

 etc. 



(b) Short Antennaed Flies (Brachycera). Mostly large 

 insects, with three short antennas consisting of three joints. 

 The following families are parasitic on the domestic animals 

 and suck the blood: 



a. Gadflies (Tabanida) ; large flies living in woods and 

 on pastures, which attack large animals on hot summer days, 

 penetrate their skin, suck their blood and thus harass them; 

 after they have left the animal a drop of blood oozes to the 

 surface of the skin from the punctured spot. 



Among the numerous varieties the cattle gadfly (Tabaniis bovinus) a fly 27 

 mm. long is most frequent, and principally annoys cattle; similar flies are the 

 T. autumnalis, T. morio, T. tropicus, the T. lineola and others. 



Haematopotae; narrow, longish flies with white-dotted wings; their chief 

 representative is the rain gadfly (Haematopota pluvialis) which harasses the animals 

 on the approach of stormy weather. 



