1896] FLOWERS AND INSECTS 161 
larger Diptera predominate. Both authors distinguish these 
cases from the dark colored flowers, like Stapelia, Asimina, etc., 
which they consider to be adapted to flesh flies. The view 
in regard to the greenish yellow flowers does not seem. to 
have been supported, if not entirely refuted, by subsequent 
investigations. Kerner’s view (16) that these colors are 
specially attractive to flesh flies was never held either by Del- 
pino or Miiller, and so may be considered to be supported 
neither by authority nor recorded observations. Of the green- 
ish yellow flowers which bloom in my neighborhood I have 
found a preponderance of general Diptera on none except 
Sassafras. Indeed I expect Smilax herbacea and S. ecirrhata to 
show a preponderance of flesh flies, but they differ from the 
others, and from all of the cases cited by Kerner, in having a 
scent of carrion. ; 
The following table gives results of observations of insect 
Visitors of Rhus in cases in which the species have been identi- 
fied. The Andrenidae and lower Hymenoptera preponderate 
over the Diptera. In the Tyrol Schulz saw R. Cotinus very 
abundantly visited by a set of insects which in a general way 
must resemble my list for R. glabra (19). 
. ‘ Other ~ * : Other Total 
Apide Andrenidz Dipteria : ve 
Rhus Cotinus— Low Geers’ ay 
Germany — Miiller I 3 6 6 . ad 
(4,14) 
Rhus_typhina — Low 
Germany — Miiller I I ee os I 3 
R (4, I 4) A : 
hus glabra—Illinoi 
(toy - 3 16 13 25 I 58 
hus Canadensis — 
2 
Illinois (19) 21 I 9 :. 33 
Ruus CANADENSIS Marsh. R.aromatica Ait. Thisisa slender 
shrub growing on high creek banks, the stems rising from 1 to 2" 
high. - The branchlets are terminated by clusters of about 
three small, head -like racemes, which measure 8-10" in. 
> and appear before the leaves. The flower buds escape 
fom hibernacula whose scales still clasp the bases of the stalks. 
