1917] Marchand— Notes on the Habits of the Snow-Fly (Chionea) 147 



the place where the snow-covering bordered on the wood of the 

 railing, the insect was never seen going on the wood, showing a 

 well-marked preference for the snow. Arrived at the end of the 

 balcony, the Chionea had to be stopped in order to prevent it from 

 falling; this was done by approaching it with the finger, avoiding 

 actual contact. This was found sufficient to cause it to change its 

 course. If carefully touched with the tip of the finger, it con- 

 tracted all the legs towards the body and remained quiet. After 

 making two attempts to go in the previous direction, it finally 

 turned to the side, and continued to run in a straight line along- 

 side the transverse railing of the balcony in the same way as 

 described before. 



The fly was then placed in its cage, where it at once started climb- 

 ing the glass walls. Shortly afterwards, at 1 p. m., it was again 

 found sitting on the underside of the cover, this time under the 

 glass plate. At 2.30 p. m., however, it was found to have resumed 

 its favorite resting-place, under the wire-cover in its open part, 

 at the edge of the anterior glass cover, that is, at the coldest spot. 



On November 26, a very sunny day, observation was omitted in 

 the morning. At 2.30 p. m. it was found that the snow in the cage 

 was melted and the Chionea was lying motionless in the melting- 

 water, apparently dead. However, as I knew from my experience 

 that drowned caterpillars may often be revived, an attempt was 

 made to bring the Chionea back to life and was successful. The 

 insect gradually began to move its legs and antennae, until, at 

 4.30 p. m., it had regained its normal condition. It was then 

 placed back in the cage. 



During the efforts to revive the insect, it was kept in the heated 

 room at least part of the time, in order to facilitate the evaporation 

 of the water. A piece of blotting-paper was used first to absorb 

 the excessive moisture. Blowing seemed to aid it in resuming its 

 movements. When these had been started, however feebly, a 

 piece of snow was brought to touch the claws of the feet, and it 

 was noticed that each time the leg responded with a considerable 

 reaction. In fact, snow touching the feet proved to be the strong- 

 est stimulus to cause them to move, and I conclude therefore 

 that normally the contact of the tarsal claws with the surface of 

 the snow is the necessary stimulus for Chionea to keep moving 

 continually, as to remain on one place might cause it to freeze. 



