94 BULLETIN UNIVERSITY OF MONTANA. 



cause of the great number of baldfaced hornets which seemed to have 

 possession. Not a Polygonia was seen. 



In 1905 album was carce. Its place was taken by the bald-faced 

 hornet. This latter insect practically prevented butterfly collecting. 



MOUNTAIN SWARMING OF VANESSA CALIFORNICA. 



During an ascent of Mount Shasta, made in August, 1889, a most in- 

 teresting occurrence was noted in the flight of countless myriads of but- 

 terflies (Vanessa californica) at an altitude far above snow-line. 



In our early morning climb of August 29, of the above year, we had 

 left our horses at half past 4 o'clock, at what is known as "Horse Camp," 

 at very near snowline, where there were many small snowfields close 

 about us. Our progress was very slow and tedious, being all of the time 

 over loose, sliding fragmentary rocks, or the almost smooth, hard-frozen 

 surface of the icy snow, and which latter did not soften till long after the 

 sun had swung high enough to shine full upon it. Some little time after 

 daylight, but long before we could see the sun, as he was hidden from us 

 by the high crest of a sharp ridge on the southwest aspect of the mountain 

 (our ascent being made from Sissons, west of the mountain), a few signs 

 of insect life were seen in the shape of "snow-fleas," two or three large- 

 winged grasshoppers, and, occasionally at first, a butterfly. The last two 

 were stiffened by the cold as if they were there from the day previous. 

 The latter insect increased much in numbers as we ascended, and were 

 many of them found in among and under the loose stones as well as a 

 few upon them. 



At perhaps half past 9 we came to a point upon which the sun had 

 long been shining, and here they were flying in the air, the flight being 

 in a south-easterly direction. From here they seemed to increase very 

 rapidly in numbers up the remainder of the ascent to well toward the 

 summit. The latter was reached at 11:20 A. M.; the temperature was 

 noted at 42 Fah. in the open air. We remained here about a half hour, 

 then passed down by way of the Hot Sulphur Springs, and then out on 

 the southerly face of the mountain. We again encountered our beauti- 

 ful friends at not farther than six ov eight hundred feet below the ex- 

 treme peak, and now in countless numbers, filling the air with their 

 flashing wings, and all passing in the same direction as observed during 

 the ascent — towards the southeast. This strange sight continued until 

 we seemed to pass below them, at an altitude of between 11,000 and 12,000 

 feet. The fact of its being a continuous flight of these insects across 

 the mountain in one direction during the warm part of the day — a period 

 of nearly five hours — is beyond question. That it was in progress one 

 or more days previous to that upon which I observed it is an easy deduc- 

 tion from the fact of the numbers of the insects found among the rocks 

 and stones while yet stiffened by the cold of the night air. How much 

 longer it may have continued I had no means of knowing. 



Where they could have come from, in such vast numbers, and what 

 brought them to such a high altitude, is of course a matter of pure specu- 

 lation. 



I had no means of preserving specimens of these insects except to 



