189^.] NATURAL SCIENCES OF PHILADELPHIA. 135 



the season, Avhen the melting is farther advanced and the snow 

 saturated with moisture, the worms appear to become more active, 

 and can be observed moving about in the shallow pools and lakelets 

 which form on the surface of the glacier. 



' ' When the snow entirely disappeared and the hard ice surface of 

 tlie glacier appeared, the snow-worms were observed in the Avater 

 which formed in the narrow crevasses. In my notes of August 2, 

 I find the following: ' Collected some black worms to-day in a 

 crack of the glacier — found them in the water of a high, narrow 

 crevasse. Observed them on the edge of the submerged snow at a 

 depth of five feet below the surface. The worms seem to have a 

 browner color than when found on the snow earlier in the season. 

 Some of the specimens I obtained had also distinct Avhitish bauds 

 around their bodies.' 



" This variation in color is noticeable in the specimens collected 

 in spring and late summer. As may be supposed, there is a 

 marked absence of animal life on the surface of the glacier, which 

 has an estimated length of seventy miles and a width of twenty- 

 five or thirty miles. Wild geese were found nesting on the terminal 

 moraine near the coast in June. The desolate mpnotony of the 

 snow horizon was broken only on two or three occasions by the 

 appearance of two species of Arctic gulls. Six species of moths, 

 four species of spiders (one new species), and a number of flies, 

 which included two or three new species, were collected on the 

 glacier. The only insect found associated with the snow-worms 

 was a minute black Thysauurian, which resembled at first glance a 

 flea. This has been determined by Dr. Henry Skinner as Achorutes 

 nivicola. These insects were found continuously and constantly 

 associated with the worms in the dry snow, and, later on, in the 

 pools of water. They Avere very active and leaped about like fleas. 

 In no instance were lichens observed associated with the Avorms. 

 although at several localities on the glacier pale crimson spots on. 

 the snow indicated the presence of the minute cryptogamic planis 

 (Protococcus nivalis) Avhich give rise to the ' red snow ' frequently 

 observed by Arctic travellers. The mean temperature of day and 

 night on the expedition has not yet been computed; but I should 

 estimate that the mean temperature at night was about 32°, and 

 in the day about 55°." 



It is a remarkable and interesting fact that the insect fauna of 



