64 BUUL-ETIIsr 1089, U. S. DEPARTMENT OE AGRICULTURE. 



yearlings can be driven into the corral, and the young animals treated 

 during the fawning season. Extraction of the grubs is apparently a 

 safe procedure. Experiments were made to determine whether injec- 

 tion of the juices contained in the larvae would seriously affect the 

 reindeer. While some slight results were obtained, it was proved in 

 a few cases that reindeer can withstand large doses of the warble 

 fluids. In the latter part of April and early in May the warble 

 grubs are large, and their skin is very tough, so that it is unlikely 

 that they would be ruptured during the process of removal. Besides, 

 as a reindeer skin is soft and pliable, the squeezing out of the grubs 

 presents no difficulty. Theoretically, if all warble larvae were thus 

 squeezed out and destroyed, there should be no flies left to attack the 

 animals. Unfortunately, warble flies are able to travel long dis- 

 tances, and seem to have the power of following animals and of catch- 

 ing up with a herd. 



It was suggested to one reindeer owner some years ago that he try 

 the following method : After most of the grubs have left the reindeer, 

 about July 1, drive the animals as far away as possible from the point 

 where the grubs have fallen, the idea being that when the flies emerged 

 from the pupal cases they would not find any reindeer to attack, 

 and as they only live for a few days they would soon die. The 

 owner, A. H. Twitchell. reported a measure of success from following 

 this method : and. when his herd was visited, it was remarked that the 

 hides seemed to be less affected with warbles than those seen in other 

 herds. It is thought that the distance which reindeer must be driver 

 should be not less than 15 miles, but the point has not been definitely 

 settled. 



In connection with the elimination of warble flies it is interestinc 

 to note that the St. Lawrence Island herd has been free from warbles 

 ever since it was established. The reindeer were derived from the 

 same sources as the other Alaskan herds. It would appear that the} 

 may have been transported to the island after all the grubs had left 

 their backs and before egg-laying had started. St. Lawrence Islanc 

 was visited during the summer of 1921 and the matter was investi 

 gated. No sign of either Oederrmgena tararidi or GepTienoinyu 

 nasalis, the nostril fly, was seen. 



Lapp names for 0. tarandi are as follows: The larva is callec 

 gourma or gourbma ; and the imago or fly, batta-bosska. 



NOSTRIL FLIES (CEPHENOMYIA NASALIS) (C. TROMPE). 



The nostril fly of reindeer is a blackish beelike insect with a rounc 

 abdomen. Its habits are quite unlike the warble ^y. and it cause; 

 far more annoyance to reindeer than the latter. It has about the sam< 

 seasonal activity as the warble fly, or from June to September, bu 



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