Robertson — Flowers and Insects. 443 
The deeply concealed nectar, the rose color and the large 
size of the flowers suggest adaptation to bumble-bees, which 
are, in fact, the principal visitors. The stamens and styles 
project so far that small insects would be quite unlikely to 
effect cross-pollination. Bumble-bees clasp the whole bunch 
of stamens between their legs. On May 5, 9 and 12 I observed 
the following visitors :— 
Apidae: — Apis mellifica L. 8, 8., whi 3; (2) sie virginicus Oliv. 9, 
S., ab.; (3) B. americanorum F. 9, s., ; (4) B. pennsylvanicus DeG. 9, 
; (5) B. separatus Cr. 9, s., freq.; %) ayabatane speciosa Cr. <j’, %., 
re 
req. 
Lepidoptera — Nymphalidae: (7) Danais archippus F.,s., one; Hesperidae: 
(8) Nisoniades juvenalis F., s., one 
CraTareus coccinea L. v. mouiis Torr. and Gray. —The 
flowers appear with the leaves, and the trees are fairly white 
with the numerous corymbs. The flowers expand about two 
and one-half centimetres. 
When the flowers open, the stigmas are found to be recep- 
tive, while the anthers are still closed. Later, when the 
anthers dehisce, there is a chance for self-pollination, with or 
without insect aid. The stamens, however, form a circle 
somewhat distant from the styles. 
In Pyrus coronaria we have observed that the superior, 
nectar-bearing portion of the receptacular tube is produced 
directly apiwards,; forming a tube, whose mouth is concealed 
y the approximated filaments. 
In Crataegus this part of the tube is expanded into a con- 
cave disc, and the filaments have no effeet in concealing the 
nectar, which is sought by numerous short-lipped insects. 
Some very small insects can obtain the nectar without 
tendering any service in return by aiding in pollinating the 
flower. Au this form the nectar-bearing disc measures six 
millimetres across. The flowers have a disagreeable odor, 
and sometimes the discs of the older flowers turn purplish. 
In 1893 I found the flowers in bloom from April 26 to 
May 16. Although the blooming time of the variety overlaps 
with that 6f the typical form, there is little opportunity for 
intercrossing of the two, since one is going out of bloom 
while the other is coming in and they are in the most favor- 
