40 



NORMAL AND EXPERIMENTAL POLLINATION. 



Merritt (1896:149) has studied the pollination of the closely related 

 Geranium richardsoni in California, where the most frequent visitors are 

 able to secure nectar without touching anthers or stigmas. However, 

 larger bees also visit the flowers, namely, Apis, Anthophora, Coelioxys, 

 Osmia, and Bombus californicus, and these readily effect pollination as they 

 cling to the anthers or styles. Robertson (1889:229; 1893:272) briefly 

 describes the behavior of the flower in G. maculatum and G. carolinianum 

 and gives a list of the visitors to each. The insect visitors of a large number 

 of European species are given by Knuth (1908:218). 



CALENDARS. 



Fifty flowers were under observation on each of the five days for which 

 the visitors are given in table 22. 



Table 22. — Visitors to normal flowers. 



Species. 



June 28, 

 30 min. 



June 29, 

 120 min. 



Aug. 17, 

 80 min. 



Aug. 19, 

 60 min. 



Aug. 20, 

 45 min. 



Apis mellifica 



Ancistrocerus sp 



Bombus juxtus 



Coelioxys maesta 



Colletes sievisiti 



Halictus pulzenus 



(Lasioglossum) sp 



Monumetha albifrons 



Prosopis basalis 



varifrons 



wootoni 



Pseudomasaris vespoides. . 



Sphex vulgaris 



Thanaos martialis 



Muscidae 



Coleoptera 



Total 



Table 23. — Visitors and visits to normal flowers. 



Species. 



July 16. July 16 



July 25. 



Bombus bifarius 



juxtus 



proximus. . . . 

 Andrena madronitens 



Colletes sieverti 



Halictus pulzenus. . . . 

 Megachile texana. . . . 

 Monumetha albifrons 

 Prosopis elliptica 



varifrons. . . . 

 Syrphus opinator 



Total 



27:24S 



0:0 



5:36 



0:0 



1:2 



0:0 



0:0 



0:0 



1:1 



0:0 



0:0 



0:0 



7:39 



