1907.] 
Gracnicher, Pollination of Wisconsin Flotvers. 
95 
C. Lepidoptera. 
Sphingidae: (17) Hemaris diffinis Bsdv., s. 
Ribes floridum L'Her. Wild black currant. 
When visiting the yellowish-green pendulous flowers of this 
species, the bees hold on to the reflexed calyx-lobes the same as 
in the case of R. gracile. The white, erect petals form together 
with the slightly shorter stamens, a tube of 3 mm. length on top 
of the calyx-tube, which is 4 mm. long. The whole tube is, there- 
fore, 7 mm. long ; it has a diameter of 3 mm. at its entrance, and 
widens out to 4 mm lower down. The anthers are situated just 
inside of the moutli of the flower, but the two-parted stigma pro- 
trudes slightly. Anthers and stigma reach maturity together, and 
spontaneous self-pollination is very apt to take place on accoimt 
of the falling of the pollen. There is a free supply of nectar at 
the bottom of the flower, but no protecting hairs are present as 
in the three preceding species with campanulate flowers. 
These flowers are adapted to bumble bees, but smaller bees also 
pay their attention to them on account of the pollen near the mouth 
of the flower. Any of these bees may be instrumental in effecting 
either self or cross-pollination, but the latter is favored by the 
advanced position of the stigma. Bees, the names of which I 
herewith present, were the only visitors witnessed on the flowers : 
Apidae : (i) Bomhiis pcnnsyl-i aniens Deg.. female, s. ; (2) 
B. separatus Cr., female, s. ; Andrenidae : (3 ) Andrena nivalis 
Sm., female, c. p.; (4) Halictns coriaceus Sm., female, c. p.; 
(5) H. forbesii Rob., female, c. p.; (6) H. vcrsatus Rob., 
female, c. p. 
