RUBUS DELICIOSUS. 



27 



transferred to the stigmas from the under parts, or autogamy results as 

 the stamens are spread and brought in contact with the stigmas. This 

 bee drives Halictus out of the flowers and occasionally enters a flower 

 with dried anthers. Apis mellifica walks around the margin of the flower, 

 apparently because the anthers mature there first, and then across the 

 center, ignoring those with brown stamens. While it is trampling about 

 and collecting pollen, the ligule is sipping the nectar found around the edge 

 of the petals at the base of the stamens. Monumetha albifrons works around 

 the margin in similar fashion, collecting pollen in smaller amounts on the 

 under side of the abdomen, legs, and head. Andrena crataegi pushes its 

 head under the anthers, bites them open, and shakes the pollen out in 

 order to pack it on the hind legs. Vespa germanica sucks ■ nectar in 

 various positions, often entering flowers in which the anthers are quite dry. 



Variation in visits. — In order to determine the effect of time and place 

 on visits, detailed calendars were made on several different days and in 

 several places. Since these are too long to be given, the results are sum- 

 marized in tables 6 to 9. In the first series the time alone was varied 

 by making use of three different days close together, while in the second 

 the two days were taken at different parts of the flowering period. 



An hour and a half of observation at the Alpine Laboratory on June 10, 

 11, and 13 yielded the list of visitors to 100 flowers (table 6), the second 

 figure, as usual, indicating the number of flowers visited. 



Table 6. — Visitors on different days in early season. 



Species. 



Apis mellifica 22:127 



Andrena crataegi 0:0 



sp 0:0 



Bombus morrisoni 1:1 



juxtus 0:0 



Bombyliad 0:0 



Halictus pulzenus 0:0 



Monumetha albifrons. ... 1:1 



June 



5:5 

 2:2 

 0:0 

 1:1 



June 



0:0 

 1:1 

 2:2 

 0:0 

 4:4 

 0:0 

 0:0 10:10 

 0:0 I 0:0 



Musca sp 



Osmia melanotricha. 



densa 



bruneri 



Papilio turnus 



Prosopis elliptica. . . . 

 Syrphus americanus. 



Total 29:134 



June 

 10 



1:1 



0:0 

 2:2 

 1:1 

 0:0 

 0:0 

 1:1 



June 

 11 



0:0 

 0:0 

 0:0 

 0:0 

 0:0 

 0:0 



June 

 13 



8:8 

 1:1 

 0:0 



0:0 

 2:2 

 1:1 



0:0 



23:23.29:29 



