1892. } Flowers and Insects. 69 
sect aid. In absence’ of insects spontaneous self-fertilization 
may readily take place 
The nectar is ct The flowers are visited by short- 
tongued Hymenoptera and Diptera, especially species of Halic- 
tus. I have found the plant in bloom from June 14 to Oct. 15. 
On July 17 and 23 I observed the following visitors:-— 
Hymenoptera — Apidae: (1) ave mellifica L. &, s.; An- 
drenidae (2) Halictus —— Say 4, s se es fasciatus Nyl. 3, 
-; (4) H. confusus Sm. S.-and -¢.-py, : H. zephyrus 
Sin % S.; (0) H.-stultus Cr. 39, s. and c. ae ; Vespidae: (7) 
Polistes eiricds Say, s.; Pompilidae: (8) ee fulvi- 
cornis Cr., 
Dip bora Binpidaes (9) Empis clausa Rob. (MS.) s. Sa 
phidae: (10) Mesograpta geminata Say, s.; (11) Syrtta p Paes 
+, 8., ab.; Tachinidae: (12) Jurinia apicifera Wik 
Shioxis ERECTA L.—This plant is quite common in prai- 
Ties and. woods. The scapes, generally one to each plant, 
not occur, unless it eae after the Bains: clos 
rule, insect visits result in cross- teniiation between 
distinct ‘sinha but may also result in self-pollination. 
ers are visited only for pollen, and depend es- 
pecially Men Halictus. I have found them in bloom from 
April 28 to June 12. May 19 and 22 I observed as visitors :— 
ymenoptera — Apidae: (1) Ceratina dupla Say 9, ab.; 
Andrenidae : (2) Augochlora pura ene 2 abs3(3) "Halictus 
oe eet Sm. 9; (4) H. coriaceus Sm. ¢; (5) H. ligatus Say 
> (6) H. cressonii Rob. Oy 17) 1. jae. Cr. 9; (8) H. tegu- 
lari Rob. 2; (9) H. anomalus Rob. ?—all collecting pollen. 
Diptera— Syrphidae: (10) Mesograpta geminata Say ; 
(11) Sphaerophoria cylindrica Say ; Anthomyidae : (12) 
Chortophila 
Coleoptera Buprestidae: (13) Acmaeodera culta Web. — 
all — on polle 
A THRONIUM ALBIDUM Nutt.—This is one of the first 
ower of =Pring and is quite common. The flower bud ap- 
n, Proc. Acad, Nat. Sci. Phil. 1890, 272, the flower is 
fertilized before opéning. 
hg t 
spontanene, pathy 
