ECOLOGY OF FLOWERS; POLLINATION 171 
wire netting which covers a piece of fresh meat or a dish of 
syrup, and bees, wasps, and hornets will fairly besiege the 
window screens of a kitchen where preserving is going on. 
Many plants find it possible to attract as many insect visitors 
as they need without giving off any scent, but small flowers, 
like the mignonette, and night-blooming ones, like the white 
tobacco and the evening primrose, are sweet-scented to at- 
tract night-flying moths. It is interesting to observe that the 
majority of the flowers which bloom at night are white, and 
that they are much more generally sweet-scented than flowers 
which bloom during the day. <A few flowers are carrion- 
scented (and purplish or brownish colored) and attract flies. 
203. Colors of Flowers. — Flowers which are of any 
other color than green probably in most cases display their 
colors to attract insects, or occasion- 
ally birds. 
It is certain, however, that colors 
are less important means of attrac- 
tion than odors, from the fact that 
insects are extremely near-sighted. 
Butterflies and moths cannot see 
distinctly at a distance of more than 
about five feet, bees and wasps at : 
: Fic. 127. Stamens and 
more than two feet, and flies at more Pistiadtke Grape trae 
than two and a fourth feet. Prob- _ nified), with a Nectar 
ably no insects can make out objects ‘Gland, g, between Each 
: Pair of Stamens. 
clearly more than six feet away; 
yet it is quite possible that their attention is attracted by 
colors at distances greater than those mentioned.? 
1 See Packard’s Text-Book of Entomology, p. 260. 
2 See Lubbock’s Flowers, Fruits, and Leaves, Chapter I. On the general 
subject of colors and odors in relation to insects, see P. Knuth, Handbuch der 
Bliithenbiologie. 
