1979] 
O Neill — Behavior of Philanthus psyche 
21 
on the thorax. Periodic observations were made of other areas 
where there were territorial males to compare male behavior and 
territory and nest distribution, and to check for movement of 
marked males between the areas. 
Wind speed measurements were made with a Datametrics Airflow 
multimeter Model 800 VTP anemometer. Males and females for 
dissection were preserved in alcoholic Bouin’s solution which 
maintains the turgidity of the glandular tissue (Humason 1967). 
Results 
Daily Activity Patterns 
At Roggen, males and females emerge in late June, the males 
preceding the females by a few days to a week. Both become active 
daily at about 1000 and remain so until between 1400 and 1600 
hours. Females spend the night in the nest while males sleep in short 
(6 cm) sleeping burrows which they dig. After emergence from these 
burrows each morning, males perch on the low vegetation in the 
nesting area, grooming and occasionally changing perches but not 
interacting with other insects, even digging females. Males begin 
setting up territories, on warm clear days, between 1030 and 1100. 
For seven different clear days during the summer of 1977, twelve 
territories in the main observation area were censused every 15 
minutes during the observation period. Only 22% of the territories 
observed at 1100 were occupied. However, from 1130 until 1300 
approximately 50% were occupied on the average. The number 
thereafter declined, few males being present by 1600. On warm clear 
days at the peak of seasonal activity, nearly 100% of the territories 
were occupied during the afternoon hours; on overcast days, few 
males were territorial. 
Location and Characteristics of Territories 
Both nests and territories occurred in areas of generally short, 
sparse vegetation rather than in nearby areas of relatively high and 
dense vegetation or open sand (Figure 1). The mean distance from a 
nest to'the center of the nearest territory was only 35 cm (N = 29; 
S.D. 17.4; see Figure 2). Where both P. psyche and P. albopilosus 
occur in the same habitat, the former nests in the peripheral areas 
around the blowout which contain plants, while the latter nests in 
the bare, fine-grained sand in the central portion of the dune. This is 
the situation at Roggen (Evans 1975). The open sand poses restric- 
