178 Psyche [December 
more or less decomposed, showing that they had been wafted to this 
altitude the previous summer and had perished, probably from 
cold, while endeavoring to found colonies. These observations 
strengthen Forel’s and my contention that in mountainous regions 
queen ants are often borne up by air-currents to elevations at 
which the physical conditions will not permit them to establish the 
species. It is very probable that this process continues year after 
year and that it may constitute an appreciable drain on certain 
ant-populations at lower altitudes. 
2. Pogonomyrmex barbatus F. Sm. subsp. rugosus Emery. 
July 29 we visited the ancient ruins of Casa Grande, nine miles 
south of Florence, Ariz. In the rooms on the ground-floor of the 
three-storied portion of the structure still standing we found vast 
numbers of males and females of Pogonomyrmex barbatus rugosus, 
only a small portion of which were still living. The marriage 
flight of these large ants must have occurred a day or two previ- 
ously, and the swarms, for some reason, had entered the low, nar- 
row doorways of the ruin and accumulated on the floor in such 
masses that several bushels could have been collected. 
3. Pogonomyrmex barbatus F. Smith subsp. molefaciens Buckley. 
At Tempe, Ariz., the marriage flight of this ant took place at 
5 p. m., July 31, nearly a month later than the flights I observed 
many years ago in Central Texas. Thousands of males and females 
issued from the large, flat nests in the irrigated fields about the 
town and soon disappeared in the cloudless sky. On the following 
day, August 1, the fecundated females were seen in great numbers 
digging their craters in the soil. They preferred the damp margins 
of the puddles left by recent rains and the banks of the irrigating 
ditches. So numerous were the little craters that their peripheries 
were often in contact. The females were busily bringing up the 
moist earth in their psammophores as pellets one-eighth of an 
inch in diameter and depositing them near the orifice of the ec- 
centric burrow. 
4. Pogonomyrmex (Ephebomyrmex) imberbiculus Wheeler. 
Near Deming, N. M., I witnessed the marriage flight of this 
ant at 10 a. m., July 12. The black males were flying rapidly to 
