118 
Psyche 
[June 
88 days shorter, with little relation to Physalis, though it 
resembles the other Panurgidae. 
Astereae. The Astereae bloom 192 days, Apr. 23-Oct. 31. 
The oligoleges average 57 days, 135 days shorter. The short 
flight is not on account of the absence of the Astereae. The 
flowers which these bees visit for pollen average 93 days, 
36 days longer than the bees. 
Heliantheae. These bloom 154 days, May 25-Oct. 26. The 
9 oligoleges average 57 days, 97 days shorter. The Helian- 
theae which they visit for pollen average 117 days, 60 days 
longer. 
Other Composite oligoleges. The Compositae bloom 192 
days, Apr. 23-Oct. 31. Eighteen oligoleges average 89 days 
later in beginning, and 32 days earlier in ending, or 121 
days shorter. The flowers they visit average 107 days. 
Papers cited (titles shortened). 
1 . Robertson, C. 1899 (7). Oligotropic bees. FIs. XIX. Bot. 
Gaz., 28 :27-37. 
2. , 1914 (2). Origin of oligotropy of bees. Ent. 
News, 25:67-73. 
3. , 1924 (4). Flower visits of insects. Psyche, 31; 
93-111. 
4. , 1925 (10). Heterotropic bees. Ecology, 6:412-36. 
5. , 1928 (10). Flowers and insects XXV. Ecology, 
9:505-526. 
