3o8 
Psyche 
[December 
emerged or been captured earlier. In 1964, the last 3 raids seen 
(August 27, 29, and September 3) yielded only 60, 47, and 37 pupae 
(no larvae) ; and there were only 82, 62, and 47 ants participating. 
It looked as if the raiding season would end soon after observations 
stopped on September 4. In 1965, on the last raid seen (September 
3), 63 ants brought back only one pupa. Observations ceased on 
September 7. 
NUMBER OF RAIDS MADE IN A SEASON 
If, as we suppose, the raiding season begins about the middle of 
June, when pupae are accumulating, and lasts through the first or 
second week of September, by which time larvae will be gone and 
pupae are becoming scarce, then the raiding season consists of about 
85 days. During 1964, the colony was observed on 50 days, during 
which time there were 29 raids on 24 days. Twenty-three of the 
raids were successful, while on 6 no brood was found. On this 
basis there may have been approximately 49 raids during the season — 
39 of them successful and 10 unsuccessful. In 1965, during 54 days 
of observation, there were 34 raids on 22 days. Twenty-nine were 
fruitful and 5 were not. In an 85-day season the ants may have made 
54 raids — 46 successful and 8 unsuccessful. 
In the 2 seasons there were multiple raids on 30% of the raid days 
observed — 1 1 days of double raids and 3 of triple ones. 
LOCATION OF COLONIES RAIDED 
The Polyergus colony at 0-26 nested in a little hollow in a field 
which sloped down to a marsh at the southeast and up to woods on 
the north and west. There were F. p. nitidwentris colonies in all 
directions, but they were not randomly distributed. F. p. nitidwen- 
tris avoided nesting in woods or marsh, in heavy grass cover, in low 
spots on the field, and in a barren spot where gravel had been dug. 
Favorable places were on the grassy upland slope among sparsely 
scattered oaks (8 colonies), along a jeep road which made an open 
strip between marsh and woods (7 colonies), and in the lower field 
wherever vegetation was not too dense (4 colonies). The Polyergus 
raiding territory had a very irregular boundary which extended for 
286 feet to the north and 114 feet to the northwest across fields, 218 
feet to the west along the jeep road, 58 feet south toward the marsh, 
and 65 feet east to the gravel dig. 
Measurements were taken of the distance travelel on 54 raids. The 
mean distance was 75 feet. On their longest raid the ants traveled 
over a little hill, across a valley, and up another hill to arrive exactly 
