Vol. xxiii] ENTOMOLOGICAL NEWS 459 
pollen from plants of the same genus, but each of the other 
ten has its own flower, so there are eleven sets which are 
absolutely without competition among themselves. I think it 
is clear that so many species could hardly flourish in the same 
locality and complete their flight in so short a time, if all were 
in competition for the pollen of the same flowers.” This 
refers to vernal Andrenas and the four species are oligo- 
tropes of Salix. If the several species of Salix afford an un- 
usually rich supply of pollen, it is not inconsistent with the 
theory of avoidance of competition, if several oligotropic An- 
dvenas compete for their pollen. 
Lovell also says: “The social bees, as a rule, visit a great 
variety of flowers, though in Europe it is stated that there 
is a bumble-bee (Bombus gerstickeri) which visits a single 
species of monkshood (Aconitum lycoctonum).” In this form 
the case is a nature-fake, as pointed out in the Botanical Ga- 
zette 28:34, 1899. In his Handbuch der Bliitenbiologie, 114, 
Knuth says that Bombus gerstickeri visits exclusively the 
flowers of Aconitum lycoctonum. This is simply a misstate- 
ment of an observation of Dalla Torre. This author did not 
say and did not suppose the B. gerstdckeri limited itself to A. 
lycoctonum, but only the female did. The males and workers 
have different habits and the difference was designated by the 
term Heterotrophy. Not even does the female limit itself to 
A. lycoctonum, for it was observed by Frey-Gessner and Hoffer 
on A. napellus (Vol. 2:52, 54). This still limits the female to 
Aconitum. They are apt to spoil this, if they keep on observing 
the habits of B. gerstickeri. 
In a paper on Colletes (Univ. Neb. Cont. Dept. Ent. No. 1) 
on page 14, Mr. M. H. Swenk refers to my statement that C. 
brevicormis is an oligotropic visitor of Specularia perfoli- 
ata and says: “In Nebraska, however, it visits also the closely 
allied Campanula rotundifolia, while I have a female taken on 
Melilotus alba. In Texas it occurs on Callirhoe involucrata and 
Asclepias latifolia, while the types of opuntiae were taken 
on Opuntia and Campanula.” I have taken the male on Pasti- 
naca and the female on Psoralea. Mr. Swenk evidently mis- 
