14 CmCULAE 8 2, U. S. DEPAKTMENT OF AGKICULTTJRE 



concerted action on the part of reindeer owners. Investigations al- 

 ready made disclose pertinent information regarding the life history 

 of the warble and nose flies responsible for the grubs in reindeer, 

 which is given in Table 1. These studies are being continued in 

 greater detail in cooperation with the Bureau of Entomology of 

 the department. 



Table 1. — Ohscrvations on warhle and nose flies 



stage 



Warble fly 



Nose fly 



Common emergeBce of grubs 



Greatest abundance of grubs 



Common appearance of flies 



Greatest abundance of flies 



Approximate life of fly 



April 22 to June 22 (2 months) 



Latter part of May 



June 25 to July 25 (1 month) 



First half of Julv 



Female, 4 to 6 days: male, 6 to 9 

 days. 



April 22 to June 7 (1^^ months). 

 Middle to latter part'of May. 

 June 15 to July 25 (IH months). 

 Latter part of June. 

 10 to 13 davs. 



From Table 1, it will be noted that in the case of the warble 

 the last emergence of grubs is at about the time of the first appear- 

 ance of the fly, on about June 25, and in the case of the nose grub 

 about June 15. This then suggests a definite period for controlling 

 them. The flies are short lived and do not travel any great distance ; 

 therefore, if the herd is moved away from the area where grubs have 

 been dropped prior to any considerable hatching of fldes, the herd 

 may largely escape them. The period of emergence of flies of both 

 the nose grub and the warble grub ends about July 25. Conse- 

 quently, the herd must be held away from the infested area during 

 this time and long enough in addition to insure that the last fly has 

 died, or until the first part of August. The time of emergence of 

 grubs is during the reindeer fawning season, April 15 to June 20. 

 The herd at this time should be closely confined to a definite small 

 area in order to have all the grubs drop in this one place. This area 

 should be located at least 15 miles from the corral site and early 

 summer range and should be used each year only during the two 

 months of fawning and the emergence of grubs. Preferably this 

 location should be inland from the coast, bordering the winter range, 

 so that the grubs will be dropped away from the summer range of 

 one's own herd as well as that of adjoining herds. At the end of the 

 spring period — that is, June 20, which is also the date for beginning 

 the summer round-ups — ^the herd should be prompth' moved at least 

 15 miles away to the coast for corralling and summer pasturing. 

 Here they should be held at least one and one-half months, or until 

 about August 10. To fix these dates firmly in mind, they may be 

 summarized as follows : 



April 15 to June 20 — Hold herd on restricted spring range for emergence of 

 gi'ubs. 



June 20 to 25 Move herd 15 to 20 miles away for summer pasturing 



and for corralling. 



June 25 to August 10_ Keep herd 15 to 20 miles away from grub and fly 

 infested area. 



It is important that the herd be moved far enough away, not only 

 from its own fawning ground but also from that of adjoining herds, 

 to obtain as complete protection as possible by this means. Along 

 the coast in most cases this will necessitate holding the herds 15 to 



