94 Wisconsin Academy of Sciences, Arts, and Letters. 
tegerrima produce flowers in great abundance, and are very at¬ 
tractive to many species of Andrena besides the two oligotropic 
species of the family flying during the maximum. In addition 
to the plants mentioned in connection with the oligotropic vis¬ 
itors various species of Viburnum, Crataegus, Cornus, Kibes, 
Rubus, etc., supply many of the species forming the spring-max¬ 
imum with pollen and nectar. From this maximum on there is 
a gradual decline of the curve until a minimum is reached, ex¬ 
tending from about July 17 to July 20, and represented by a 
single species. At the end of the third week in July a renewed 
increase sets in, culminating in a maximum of the summer- 
group of Andreninae, with 8 species in evidence at the end of 
August and the beginning of September. This summer-group 
comprises altogether 11 species, and these are with but one 
exception oligotropic bees of the family Compositae. The plants 
of this family with the numerous species of Solidago, Aster, 
Helianthus, Kudbeckia, Eupatorium and many other genera are 
dpminant factors in the make-up of the flora of the late sum¬ 
mer months. The earliest species of goldenrod begins its bloom¬ 
ing period about the middle of July, around the 20th of the 
month the first aster appears, and mostly a trifle later the first 
sunflower. Corresponding with the appearance of these com- 
posite flowers the earliest Andrena of the summer-group A. peck- 
hami begins to fly about July 21, and before the end of the month 
3 additional oligotropic visitors are present on these flowers. 
From the first week in September on there is a falling off in the 
number of these bees, and around October 8th Andrena asteris, 
the last one of the A.ndrcninae disappears. Although any one 
of these visitors of the Compositae may collect pollen from flow¬ 
ers belonging to different genera of the family,. they still show 
a decided preference for certain genera. A. peckhami, A. cly- 
peonitens, A. aliciae and A. kelianthi favor the sunflowers', A. 
nubecula, A. americana, A. solid aginis and A. persimilis the 
goldenrods, A. asteris and A. graenicheri the asters. 
The exceptional position held by Andrena parnassiae, the 
oligotropic visitor of Parnassia Caroliniana has been referred to 
above. This is so closely related to A. peckhami, and the two re¬ 
semble each other to such an extent as to leave no doubt regard- 
