MENTZELIA MULTIFORA. 



57 



of Bombus and Apis are seen hovering around them, landing at the buds 

 and inspecting them carefully. When the flowers open, the visitors appear 

 at once in fairly large numbers and immediately commence collecting 

 both pollen and nectar. The number grows less as the sun goes down, but 

 persistent visitors are present and working until dark. This is particularly 

 true of Bombus occidentalis. Table 42 gives the list of visitors to normal 

 flowers on succeeding days, the first from 5 h 00 m to 6 h 40 m and the second 

 from 5 h 00 m to 5 h 55 m in the afternoon. 



EXPERIMENTS. 



CREPE-PAPER COROLLAS, AND COMPETITION. 

 Crepe-paper corollas. — Red, white, yellow, green, and blue paper 

 corollas were fastened below the stamens after the petals were cut off. 

 This was done about 4 p. m., when the buds were beginning to open. Indi- 

 vidual flowers of Chamaenerium and Geranium were also paired with these of 

 Mentzelia in the group under observation, so that competition studies could 

 be made at the same time. Before the calendar given below was made 

 the flowers were observed as they opened. At that time the visitors were 

 already in the vicinity, keeping watch of the flowers. In putting on the crepe 

 corollas the stamens were exposed, and nectar and pollen made accessible. 

 As a consequence, paper flowers of all colors were visited, yellow more than 

 the others and green less often, doubtless because of the resemblance to 

 the leaves. The yellow flowers so closely resembled the normal ones 



Calendar 1. — Visits to 



S'W Apis mellifica 1. 



5 01 

 5 15 

 5 16 



521 B 



5 25 

 5 30 



Bombus juxtus 1. 



B. juxtus 1. 



B. occidentalis 2 Mentzelia of Gera- 

 nium pairs, 6 Mentzelia of 

 Chamaenerium pairs, 

 juxtus 4 Mentzelia of Chamae- 

 nerium pairs. 



B. occidentalis 1. 



B. bifarius 32; inspects all crepe and 

 paired flowers. 



B. bifarius 27; inspects paired Chamae- 

 nerium. 



normal and crepe flowers. 



5 h 45 m B. bifarius 50; 7 Mentzelia of Chamae- 

 nerium pairs. 



Apis 3. 



B. bifarius 48; inspects all crepe and 

 paired flowers. 



B. bifarius 1. 



B. juxtus 1; red crepe 1, Mentzelia 

 21, 33. 



Apis 5. 



B. bifarius 15. 



5 52 

 5 55 



6 02 

 6 15 



Table 43. — Summary of Mentzelia calendar. 



i = inspected; r = red. 



