442 Trans. Acad. Sci. of St. Louis. 
a common beetle, Trichius piger, which feeds upon it. Small 
bees may collect the pollen without touching the stigmas. 
The blooming time of Rosa humilis is from May 22 to 
July 8. Anthophora abrupta 9, whose time of flight is from 
May 13 to the last of June, seems to depend for pollen 
almost exclusively upon this rose. 
On twelve days, between May 22 and June 20, I observed 
the following visitors :— 
pee ae a (1) Bombus virginicus Oliv. 8 ; (2) B. ress ae oh 
orum F. Q, ab.; (3) B. separatus Cr. 2 ; (4) Anthophora abrupta Say 9, a 
(5) Synhalonia speciosa Cr. 9; (6) Ceratina dupla Say 9; Andrenidae: en 
Halictus confusus Sm. 2; (8) Augochlora pura Say 9; (9) Agapostemon 
viridula F. 9 —all collecting pollen. 
Coleoptera — Scarabaeidae: (10) Trichius piger F., ab.; Chrysomelidae: 
(11) Diabrotica 12-punctata Oliv.— both feeding on pollen. 
Rosa seTiGERA Michx.— The flowers resemble those of 
Rosa humilis, but the styles cohere in a column, which 
enables the stigmas to touch a visiting bumble-bee a little 
more readily. I have noted the flowers in bloom from June 
16 to July 4. June 161 saw them visited for pollen by (1) 
Bombus americanorum F. ¢; (2) Anthophora abrupta Say 
23 and (3) Trichius piger F. 
Prrus coronaria L. — During the blooming time — April 
25 to May 16 — the trees are conspicuous with a profusion of 
rose-colored flowers. The attractiveness of the flowers is 
increased by their delicious fragrance. 
The corollas expand from four to five centimetres. The 
receptacular tube extends nearly directly upwards from the 
ovary for a distance of about two millimetres. The summit 
of the tube is surmounted by a dense circle of filaments which 
are also directed upwards and a little inwards. In this way 
the nectar is effectually concealed and short-tongued and 
weak insects are excluded. The nectar is reached by a bee 
thrusting its proboscis between the separating ends of the 
filaments. The flowers are strongly proterogynous. In most 
of them the stigmas are protruded so far beyond the anthers, 
that spontaneous self-pollination after the anthers begin to 
dehisce is impossible. 
