INSECT POLLINATION IN COLORADO 4S5 



On Primula angustifolia was seen a Bombus; on Frasera steno- 

 sepala, rare above timber line, was found 



Halietus rasiphorae Cresson. 



Halietus regis Cockerell (n. sp.). 



On Castilleja sulphurea was a. Bombus kirbyellus Curtis, which 

 had just visited Trifolium dosyphyllum; on Alsimopsis obtusiloba 

 was apparently a species of the little red parasite, Sphecodes ; on 

 Hcuchera parvifolia a small bee; on Phlox caespitosa a small bee; 

 on Sievcrsia turbinata, a species of Prosopis; on Arenaria fend- 

 leri, Prosopis coloradensis Cockerell; on Thlaspi coloradense, 

 Halietus sisymbrii Cockerell; on Erigcron pinnatisectus, Prosopis 

 coloradensis Cockerell and Prosopis personatella Cockerell 

 (n. sp.). 



The plant most conspicuous and visited by the greatest number 

 of insects is the sunflower-like Rydbergia grandiflora. The only 

 bee noticed on it was a green form, probably Angocholora, seen 

 three times. There were numerous butterflies, among them Melit- 

 tia, Lycaena, and a white form. Among the very many flies are 

 Syrphidae and Anthomyineae. Butterflies seem to take a greater 

 fancy to it than to any other plant of the region. 



The plant which seemed most noticed by flies is the very com- 

 mon Sievcrsia turbinata. Among these ever-present guests are 

 Anthoniyineae and Empididae. Ants also are found here. 



There are several other flowers that seem open to the ap- 

 proaches of flies and ants. The most important are Dryas 

 octopetala, Potentilla uniflora. Lloydia serotina, Micranvthes 

 rhomboidea, Caltha, Polygonum bistortoides, Oreoxis alpina, 

 Arenaria fendlefi, Eriysimum wheeleri, Ranunculus adoneus 

 and Heuchcra par vi folia. Some of these flowers are very con- 

 spicuous and others but slightly so, but all agree in having the 

 nectar practically exposed and in the reach of all comers. The 

 Anthonryineas are easily the prevailing forms among the flies, 

 although Syrphidae are quite common. Aliiller finds Caltha, 

 Dryas, the Potentillas and the Ranunculi visited mainly by flies 

 in the Alps. 



A bumble bee, probably Bombus cdwardsii bifarius, was seen 

 entering a hole among the rocks above timber line, doubtless 

 leading to its nest." A male specimen of Osimia abnormis Cres- 

 son, was taken from the rocks where it was apparently seek- 

 ing shelter from the wind. I desired to learn the extent to 

 which the alpine flowers are dependent upon insects for their 



