212 THE AMERICAN NATURALIST. 
characteristic of many genera there has been much contraction 
attended by the elimination of axes, leaves, bracts, and even 
of the perianth, but the flowers are not degraded entomoph- 
ilous forms. Consequently, when the flowers possess bright 
colors they are not the relics of a higher stage of coloration 
developed by the selective tastes of insects, but are due to the 
chemical constitution of the nutritive fluids and the action of 
light and heat. 
2. The absence of blue is noteworthy. Yellow is not com- 
mon, but is well shown in the scales and calyx of Betula. The 
inner side of the calyx of Mollugo verticillata is whitish, and 
in Polygonum the margins or entire calyx is white. Red is 
very common and occurs in many genera. Purplish flowers 
also occur, as Sesuvium maritimum. There is evidence derived 
from this group of families that if anthophilous insects were 
devoid of color sense, they still would have developed white, 
yellow, red, and purple flowers, though they would be less 
frequent and of duller shades. 
3. A number of genera have become entomophilous, and 
this change in the manner of fertilization has been attended 
by an increased conspicuousness of the flowers. The anthers 
of Salix, formerly a wind-fertilized genus, have become a 
brighter yellow; in Aristolochia and Asarum the calyx is a 
lurid purple attractive to small Diptera; and in Polygonum 
and several other genera clear white or deep red. Insects 
have not in these instances produced new colors, but have 
intensified those already partially developed. 
4. Petals are usually present in the Portulaceze and Caryo- 
phyllacez, and are white, yellow, red, or purple. The smaller 
white flowers of the Caryophyllacez are visited by flies, beetles, 
and the short-tongued bees, which may have aided in the pres- 
ervation of the petals and in rendering them a clearer white. 
The larger red and white flowers are correlated with the visits 
of Lepidoptera; the red species with butterflies, the white 
nocturnal forms with moths. 
WALDOBORO, ME. 
