rei:n'deer IjST .y[.ASKA. 65 



is never so numerous. Instead of laying eggs, it deposits live larvae 

 in the nostrils of reindeer. 



The method of attack is peculiar. The fly hovers for a few 

 moments in front of the nostrils, then darts in and deposits a drop of 

 wriggling larvae at the entrance to the nose. The larvae work their 

 way up the nostrils and attach themselves at the back just in front 

 of the entrance to the throat. 



The effect on reindeer of this method of larval deposition is most 

 marked. The animals are terrified by the insect's attack, and when it 

 is hovering in front of their noses they assume a terror-stricken look, 

 their eyes staring, their mouths open, and their bodies in a tensely 

 strained attitude. When a reindeer is in this rigid state, the slightest 

 touch on any part of the animal will cause muscular contractions 

 which shake the whole body, just like an electric shock. When the 

 insect deposits its larvae, such a shock follows. It is succeeded by a 

 total relaxation, the deer evidently realizing that it is not likely to be 

 struck twice by the same insect. The animal appears nauseated and 

 walks a few steps with its head elevated, sneezing and showing signs 

 3f nasal irritation. 



Once the larvae are firmly attached in their habitat at the back of 

 the nostrils, they seem to cause the reindeer very little annoyance. 

 Their growth is slow and they do not greatly increase in size until 

 about the end of March, at which time they appear to grow most 

 rapidly, attaining their full size in the early part of May. The first 

 larva seen to emerge appeared on May 12. The last date of emer- 

 gence has not been ascertained definitely, but presumably it is about 

 the same as for the warble fly. 



When the larvae are mature they cause the reindeer much suffering 

 and annoyance. Two young animals which were kept at the Una- 

 lakleet station were watched carefully, and it was observed that the 

 larvae kept them in a constant state of worry, even when they were 

 at rest. They would elevate their heads and sniff in an evident 

 attempt to dislodge the parasites. At other times they coughed 

 and sneezed. But though these attempts to dislodge the parasites 

 were almost continuous, the reindeer seldom appeared to use really 

 vigorous efforts, apparently owing to fear. The expulsion of the 

 larvae was observed on several occasions, and almost invariably when 

 a larva fell to the ground it was red in color, being coated with a 

 thin film of blood. 



It is surprising to note that nasal discharges in reindeer are slight 

 in comparison with those of sheep when the latter are harboring 

 Oestrus ovis, which is very similar to the reindeer fly in habits. 

 Reindeer, however, show symptoms of staggers, or "false gid," such 



105932°— 22 5 



