138 
Psyche 
[December 
was 9:23 a.m. (64°). Extremes for beginnings of female 
flights were 5:30 a.m. (67°) and 10:40 a.m. (64°). 
Flights varied greatly in their duration, depending upon 
how fast the temperature rose. The longest flight lasted 
from 5:28 a.m. to 8:05 a.m., but it started early in a 
dense fog, and later, after both males and females were 
flying, flight was interrupted for an hour because wings 
became too wet to be used. One of the shortest flights, 
lasting 32 minutes, was one of the abundant ones. This 
occurred on September 1 after two days of bad weather, 
and an estimated 1750 ants flew. It was a sunny morning 
and the temperature rose very rapidly from 9 :03 a.m. 
(58.5°) to 9:35 a.m. (72°). On this day males flew for 
22 minutes from 9:03 a.m. to 9:25 a.m. (69°) and females 
for 21 minutes from 9:14 a.m. (63.5°) to 9:35 a.m. 
The ending of flights varied greatly as to time. Males 
have stopped flying as early as 6 a.m. or continued as 
late as 9 :45 a.m. ; females as early as 6 :25 a.m. or as late 
as 10 :45 a.m. Flights could be stopped by rising tem- 
perature; no males were seen to fly at temperatures above 
71° nor females above 74°. But often flights ended well 
below these temperatures. On the four days when the 
most ants flew, flights stopped at the following temper- 
atures: August 20 — males 64°, females 67°; August 22 
— males 66°, females 67°; September 1- — males 69°, fe- 
males 72°; September 5 — males 70°, females 70°. Per- 
haps on fine mornings all those which were mature flew 
before the critical temperature was reached. Sometimes 
practically all those which climbed vegetation flew; yet 
at other times many returned to the nest. It seems prob- 
able that D. mariae flights began shortly after the first 
winged ants emerged from the pupal stage, and flights 
continued as others emerged. Darkening sky and lower- 
ing temperature could end .flights, and on these days many 
males and females returned to the nest. 
Flights were prevented on two days by rain, and on 
two others, apparently, by high winds. On these latter 
days, males and females were slow about climbing and 
