GRASSHOPPER GLACIER OF MONTANA — GURNEY 321 



rents on flying grasshoppers, and their observations leave no doubt 

 that uprising currents are highly significant in many long flights 

 at high altitudes. Flying grasshoppers which come under the in- 

 fluence of convection currents in some instances are liable to be swept 

 upward even to tens of thousands of feet and at velocities greater than 

 their falling speed with wings closed. Such currents are probably 

 responsible for various occurrences of grasshoppers on mountains 

 at altitudes far above their normal habitat. 



In recent years there has been a growing appreciation of the ex- 

 tent to which insects are carried by air currents. Many of the spe- 

 cies transported either fly weakly or not at all. This fact was well 

 shown by Glick (1939), who described collections made during a pe- 

 riod of several years in the Southern States by using ingenious traps 

 mounted on airplanes. I recently reviewed this and later evidence 

 which favors the occasional long-distance introduction of insects by 

 natural air movements (Gurney, 1949b). 



Further observations on the reactions of Melanoplus rugglesi to 

 external factors may be expected to show how closely this species 

 agrees with Schistocerca gregaria in its fundamental behavior. Like- 

 wise, further collections from the layers of frozen grasshoppers in 

 the glacier may eventually disclose specimens of rugglesi. These 

 would be of much historical importance, because they would show that 

 flights occurred long ago, though we now lack flight records earlier 

 than 1939. It is logical to suppose that, at irregular intervals for 

 centuries past, phase transformation of rugglesi has taken place, fol- 

 lowed by long flights. In fact, early reports of the United States 

 Entomological Commission (Riley et al., 1878, p. 106, App., p. 139 ; 

 1880, p. 7) record large numbers and conspicuous swarms of grass- 

 hoppers in the vicinity of Golconda and Winnemucca, Nev., in 1877 

 and 1878. This is the place where, about 1947, a migration of rugglesi 

 occurred, one in the series of recent annual migrations reaching from 

 Big Smoky Valley, Nev., to Guano Lake, Oreg., over a period of about 

 12 years. Circumstances suggest that the same grasshopper may 

 have been involved in 1877-78, rather than the Rocky Mountain grass- 

 hopper as then supposed. No preserved specimens are known, how- 

 ever, and consequently the identities cannot be established. Grass- 

 hopper Glacier may yet contribute much of interest to the early 

 as well as the current history of this Great Basin grasshopper. 



OTHER LOCATIONS OF FROZEN GRASSHOPPERS 



Although this account has been concerned mainly with Grasshopper 

 Glacier, there is no doubt that grasshoppers which have been trans- 

 ported partly by air currents have frozen into glacial ice in many 

 places. Bevan and Dorf (1932) mention a second "grasshopper 

 glacier" of the Beartooth Range, located at the head of the West Fork 



