100 



COMPETITION AND CONSTANCY. 



nectar. P. secundiflorus possesses a pink-purple corolla with a wide throat, 

 while that of P. barbatus is a flaming scarlet with a narrow throat and hence 

 excludes the larger bees. The flowers of Scrophularia nodosa are small 

 and of a dull mottled color, but these disadvantages are offset by the 

 abundant nectar. Those of Aquilegia coerulea are large and showy, the 

 sky-blue color making them exceedingly conspicuous; they contain much 

 pollen and nectar, but the latter is unavailable to many of the visitors. 

 The deep-blue flowers of Mertensia alpina are relatively small, with a narrow 

 throat, and are borne in small clusters. However, they possess a delightful 

 fragrance, which is indicated by their local name, "forget-me-nots." Table 

 67 contains the record for 1 hour 15 minutes, from 10 h 45 m a. m. to 12 m. on 

 July 4, and table 68 for an hour, 10 h 20 m to ll h 20 m a. m. on July 12. 



Table 67. — Rubus, Pentstemon, and Scrophularia. 



Table 68. — Rubus, Aquilegia, and Mertensia. 



Species. 



Plant, R. 

 strigosus. 



Bouquet, A. 

 coerulea. 



Bouquet, M 

 alpina. 



Apis mellifica 



Andrena crataegi 



madronitens 



Andronicus sp 



Bombus juxtus 



Halictus pulzenus 



Megachile texana 



Monumetha albif rons 



Osmia densa 



Prosopis sp 



Pseudomasaris vespoides 



Muscidae 



Atrytone taxiles 



Total (Apis) 



Countless. 

 1: 1 



16:20 



1: 1 



0: 



0: 



1: 1 

 20:66 



7: 9 



1: 1 



1: 2 



0: 



0: 



0: 



4: 4 



1: 1 



36:85 



0: 

 0: 

 0: 

 0: 

 0: 

 0: 

 0: 

 0: 

 1: 1 

 6: 6 

 0: 

 2: 2 

 1: 1 



10:10 



Summary. — In both cases the honey-bees were so numerous that they 

 could not be counted at the same time that the other visitors were noted. 

 In the first experiment Pentstemon secundiflorus was nearly twice as attrac- 



