AMERICAN nYMENOPTERA. 285 



concerning which information was desired, and sent an admirable re- 

 port the substance of which is given. The temperature of the day 

 was 32° (Fahr.)- Hills were first examined on the northern slope 

 upon which lay snow five inches deep. The snow upon the mounds 

 was of the same depth, and had not, therefore, been interfered with by 

 the ants. A mound, about two feet in height from the vertex to the 

 level and ten feet in circumference at the base, was opened, first on 

 the northern and eastern sides. The frost had penetrated about four 

 inches from the surftice. At three inches small clusters of ants were 

 found, very stupid but not torpid ; the temperature here was 33'^. On 

 the south and west sides the frost had penetrated eight inches, and 

 throughout this frozen portion, (thermometer at 33°) from a distance 

 of three inches from the surface inward, ants were scattered, in the 

 same condition as above. The w;Jiole top of the mound was now found 



to be loosened and was inverted, giv- 

 ing a cone whose altitude A B was 

 18 inches. The hill was found to be 

 frozen only to the plane Ci> except 

 on the surface as above described. 



The temperature of the cone at 12 

 Fig. 9. — Segments of Frozen Hill. • i r. .r . of.o *.i 



* inches from the vertex was 30°; the 



temperature of the now frustrum of a cone at six inches below the 

 plane C D was 33°. There were not many ants in the cone. The 

 greatest number was found at a distance^of two feet from the vertex 

 in temperature 33°; a few at 12 inches from the vertex in tempera- 

 ture 30°, sticking in the icy galleries with as much show of life as 

 those a foot below tiiem in a temperature 3° warmer. None of tliciu 

 however were very lively. The underground galleries were then 

 examined, how far down is not stated, but no ants or other insects 

 were found. 



According to instructions, mounds entirely exposed to the sun were 

 next investigated. They lay upon the western slope from which the 

 snow had nearly all melted away except where shaded by foliage. The 

 hill reported below was entirely exposed to the sun, and of about the 

 same dimensions as that just described. On the south and west sides 

 the frust was melted out for about four inches at which point the 

 thermometer gave 40°. Then followed two inches of frozen ground 

 at 32°. On the east and north sides the fnjst was not u)clted out for 

 more than an inch; the frctzen portion extended inward four inches at 

 33°. The top of the cone was then turned over as before, and found 



TRANS. AMEK. ENT. SOC. VI. (38) DECEMBER 1S77. 



