480 SEMI-CENTENNIAL OF Torrey BOTANICAL CLUB 
flower structure. Perhaps a parallel case is that of the honey-bee, 
which was the most abundant visitor of the vervain, and is gener- 
ally regarded as catholic in its tastes, but which was not taken on 
the pickerel-weed. These cases may have a bearing on the view 
held by some entomologists that insects have less color sense than 
has been supposed, but are much more keenly attracted by odors 
of particular plants, which may not always be perceptible to man. 
Of the Hymenoptera, the following species were taken from 
the middle to the last of August: the bumble-bees, Bombus fer- 
vidus Fabr., B. impatiens Cress., B. pennsylvanicus DeGeer; and 
a smaller Anthophorid bee, Xenoglossa pruinosa Say (?) perhaps 
only gathering pollen. Of Diptera, one specimen of a large 
“horse-fly,” Tabanus giganteus ПеСеег, was perhaps only а 
casual caller.* An aggressive large blue-black bee, observed 
several times, but always eluding the pursuing reflex-camera as 
well as the net, was probably one of the carpenter-bees of the genus 
Xylocopa. Schneckt has reported that Xylocopa virginica regu- 
larly slits the lower end of the corolla tube to reach the nectary 
in Pontederia and in other plants. In the present case, however, 
I feel sure that the bee was sucking nectar from one flower after 
. another in legitimate fashion. 
Lovell reports as.visitors to Pontederia at Waldoboro, Maine, 
July 21 to August 10, 1898, two species of bumble-bees, two species 
of small cliff-dwelling bees, one collecting pollen, and four species 
of Diptera, all feeding on pollen; butterflies, he states, were com- 
paratively rare, and only Colias, Pieris, and Argynnis cybele Fabr. 
are mentioned. During one warm but cloudy afternoon in August, 
at the New York Botanical Garden, I saw no butterflies visiting 
Pontederia, but only bumble-bees. Similarly, during August, 
1917, abundant colonies of pickerel-weed growing in the open 
border of Lake Cossayuna in Washington County, New York, 
* For the identification of these insects I am indebted to Dr. Frank E. Lutz, of 
Не America bsp um of Natural History, whose Field Book of сечи published 
in January, 1918, will be a handy guide for the student of floral biology. The 
нн 5 by myself, were all compared with specimens at "n American 
Muse 
ы К, J. Further notes on the mutilation of flowers by insects. Bot. 
Gaz. 16: 313. 1801. 
ft Lovell, J. Н. Three fluvial flowers and their visitors. Asa Gray Bull.6: 63-65. 
