110 



COMPETITION AND CONSTANCY. 



The results are interesting only in showing the behavior of Bombus 

 juxtus on two successive and similar mornings. On the first the bouquet 

 of Chamaenerium approached the Geranium plant in attraction, but there 

 was a great discrepancy on the second day. Monarda received a few 

 visits on one and inspections only on the other, in spite of the fact that 

 B. juxtus can reach the nectar when it chooses. Gilia was not even inspected, 

 the visitors evidently knowing that the nectar is inaccessible to them. 



Table 76. — Plant and bouquet competition of several species. 



Expt. 1, 2 hours, 8 to 10 a.m., July 3. 



Species. 



Plant. 



Geranium Rosa 



Mixed bouquet. 



Pent. sec. Pent. barb. Scroph. nod 



Andrena crataegi 



madronitens. . . 



prunorum 



Anthophora simillima . . . 



Apis mellifica 



Bombus juxtus (worker) , 

 (queen) . . 



occidentalis 



Colletes sp 



Megachile w. calogaster . 



Osmia sp 



Prosopis episcopalis. . . . 

 Peeudomasaris vespoides 



Total 



0: 

 0: 

 0: 

 0: 

 9:27 

 0: 



0: 

 1: 1 

 0: 



0: 

 0: 

 0: 

 1: 2 

 0: 

 1: 1 



0: 

 0: 



0: 

 0: 



0: 

 0: 

 2:10 

 0: 

 5:59 



0: 

 

 0: 



0: 

 1: 7 

 0: 

 0: 

 1: 1 

 0: 

 8:54 



13:34 



31:156 



0: 



10:62 



Expt. 2, 2 hours, 10 a.m. to 12 m., July 3. 



Species. 



Geranium 



Castilleia 



Mixed bouquet. 



Apis mellifica 



Bombus juxtus 



Osmia melanotricha . . . 

 pentstemonis . . . 



Prosopis elliptica 



Pseudomasaris vespoides 



Vespid 



Selasphorus platycercus . 



Total 



6:16 

 1: 1 

 0: 

 0: 

 1: 2 

 0: 

 0: 

 0: 



0: 



0: 



0: 



1: 2 



0: 



0: 



0: 

 19:39 



0: 

 0: 

 6:19 

 6:21 

 0: 

 6:75 

 0: 

 0: 



8:19 



20:41 



18:115 



0: 

 0: 

 0: 

 0: 

 0: 

 0: 

 0: 

 0: 



0: 



0: 

 0: 



0: 

 0: 

 0: 

 8:39 

 2: 9 

 0: 



10:48 



CHAMAENERIUM ANGUSTIFOLIUM. 



Comparison. — The flowers of Geranium caespitosum resemble those of 

 the fireweed in form and color, but are somewhat larger. Perhaps the 

 chief difference between them lies in the fact that they are scattered in 

 the one and grouped in a conspicuous raceme in the other. The fireweed 

 produces more nectar, and the pollen is not only more abundant but is also 



