PENTSTEMON SECUNDIFLORUS. 



77 



Middle lobe of the lower lip removed. — Bombus morrisoni went into 

 3 flowers of this type, apparently without noting any change, and B. juxtus 

 behaved similarly. 



Upper lip removed. — Bombus morrisoni noted no change. 



PENTSTEMON SECUNDIFLORUS. 

 NORMAL POLLINATION. 

 Behavior. — Bombus proximus alights on the lower lip of the corolla 

 and then turns around on to the upper lip, standing upside down while 

 working. It flies from one open flower to another in a cluster and then 

 to the next cluster. Vespa germanica stands on the lower lip and pushes 

 its head far into the flower for nectar. It transfers the pollen collected on 

 the head to its hind legs with the front ones. After visiting many flowers, 

 it rests on the ground before going to others. 



Calendar. — A calendar is given below of visits during a 42-minute period 

 to 24 spikes bearing 125 open flowers. Holes had been bored by robbers 

 at the base of the corolla on the upper side of many of these flowers. Pseudo- 

 masaris vespoides went to many flowers twice, collecting in the usual way 

 from those previously robbed by some other insect. Anthophora simillima 

 stopped at only 2 or 3 flowers at a time and was easily frightened. Sys- 

 toechus vulgaris was a persistent visitor, going to as many as 59 flowers in 

 rapid succession. 



Calendar 1. — Visits to normal flowers. 



ll h 06 m Anthophora simillima, 1. 



11 10 Osmia melanotricha, 1; Prosopis 

 wootoni, 1 ; Pseudomasaris ves- 

 poides, 15. 



11 13 Anthophora, 1. 



11 15 Anthophora, 2. 



11 16 Bombus juxtus, 1. 



ll h 20 m Osmia, 1. 



11 21 Bombus, 1; Systoechus vulgaris, 59. 



11 27 Anthophora, 5; Megachile wootoni, c 



11 30 Anthophora, 1. 



11 34 Osmia pent3temonis, 4. 



11 45 Andrena, 1. 



11 48 Monumetha albifrons, 1. 



The variety of visitors to this species is shown by table 53, column 1 

 giving the visitors during a 40-minute period and column 2 during 48 

 minutes. 



Table 53. — Visitors to normal flowers. 



EXPERIMENTS. 



ODOR. 



Powders and extract. — Flowers were sprinkled with four kinds of 

 talcum powder. Many individuals of Bombus juxtus landed on such flowers, 



