64 BULLETIN 1089, U. S. DEPARTMENT OF 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. Twitehell, 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 driven 
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 interesting 
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 they 
may have been transported to the island after all the grubs had left 
their backs and before egg-laying had started. St. Lawrence Island 
was visited during the summer of 1921 and the matter was investi- 
gated. No sign of either Oedemagena tarandi or Cephenomyia 
nasalis, the nostril fly, was seen. 
Lapp names for 0. tarandi are as follows: The larva is called 
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 round 
abdomen. Its habits are quite unlike the warble fly, and it causes 
far more annoyance to reindeer than the latter. It has about the same 
seasonal activity as the warble fly, or from June to September, but 
