INSECT POLLINATION IN COLORADO 483 



INSECT POLLINATION OP TIMBERL1XK FLOWERS 

 IN COLORADO. 



L. A. KENOYER. 



Nageli attributes the fact that alpine flowers are more showy 

 that those of the lowlands to the greater scarcity of insects 

 on the mountain tops and the greater efforts thereby necessary 

 on the part of flowers to secure their visits. 



Bonnier states that insect visitors are quite rare on mountain 

 flowers, and uses this as an argument to indicate that flower 

 color plays a relatively unimportant roles in the attraction of 

 insects. 



Midler after extensive study of the subject states in his book, 

 "The Fertilization of Alpine Flowers," that although there 

 are long periods in which the weather of the mountain top 

 does not favor the activities of insects, he is unable to convince 

 himself that on the whole the flowers of the Alps are relatively 

 less visited and crossed by insects than are those of the low- 

 lands. 



Schroeter in his consideration of the subject is inclined to 

 deny Midler's proposition and to assert that in the Alps and 

 on mountains in general the relative number of insects that 

 effect cross pollination is less than in the lowlands. 



Little investigation seems to have been made on the abun- 

 dance and effectiveness of insect visits to flowers in our Rocky 

 Mountain region. Mrs. Soth, who has written on the flora of 

 Pike's Peak, states that insects are rare on mountain flowers, 

 only an occasional bumble-bee being seen. Therefore I took 

 advantage of a vacation in Colorado in the summer of 1915 

 to do a little work on alpine flowers and their visitors. 



During the month from June 18 to July 18, I went ten times 

 from my camp at Tolland, Colorado, to the parts of the con- 

 tinental divide above timber line, between James Peak and 

 Corona. The insects collected on these trips were identified by 

 Dr. T. D. A. Cockerell of the University of Colorado. 



The most apparent recipients of the visits of bees are the 

 mountain clovers. These plants sometimes occupy mountain 

 areas almost to the exclusion of other plants. It seemed to me 

 that in sunny weather when the wind is not too strong, bumble 



