94 Bulletin Wisconsin XaturaJ History Society. [Vol. 5,Xo. 2. 
lengthening of the style, the stigma surpasses the anthers before it 
becomes receptive. Pollination is generally due to insects and the 
flowers are, as Robertson states, adapted to bumble bee females, 
the only sex of bumble bees represented so early in the year. On 
account of their size, they are the only bees which, while hanging 
on to the flowers, are capable of sucking, and at the same time 
touching the anthers and stigma. These parts of the flower come 
in contact with the ventral surface of the base of the abdomen. 
Robertson observed 4 species of bumble bees, and in addition to 
these, 18 smaller bees which he regards as intruders, for the rea- 
sons set forth above. But in several instances I have seen some 
of the smaller bees (species of Andrena) visiting the flowers for 
nectar, and besides crawling to the top of the flower for the pur- 
pose of collecting pollen. Such visits of the smaller bees are of 
course of as much importance to the flower as the visits of bumble- 
bees, although these flowers are undoubtedly adapted to the 
latter. The exceptional visits of flies to such a flower are of 
little significance. At ^Milwaukee I have seen the following 
insects as visitors : 
A. Hymenoptera. 
Apidse : (i) Bomhiis aincricanorum Fabr.. female, s. (2) 
B. coiisiinilis Cr., female, s. ; (3 ) Xoiiiada crcssouii Rob., female, 
s. ; (4) Ccratiiia diipla, Sb,}', male, s. ; Andrenidse : {^) Andrena 
nivalis Sm.. female s. and c. p.; (6) A. niihimikccnsis Graen., 
female, s. and c. p.; (7) A. cressonii, Rob., female, s. and c. p.; 
(8) Aiigochlora confusa Rob., female, s. ; (9) Halictus 
Icroiixii Lep., female, s. ; (10) H. provancheri, D. T., female, s. ; 
(11) H. quadriniactilatus Rob., female, s. ; (12) H. conncxus 
Cr., female, s. ; (13) H. albipennis Rob., female, s. ; (14) 
Sphecodcs dcmatidis Rob., female, s. ; Eumenidae : (15) 
Odynerus philadelphice Saus, s. 
B. Diptera. 
Syrphidse: (16) Syrphus anicricanits Wied., f. p. 
