216 THE AMERICAN NATURALIST. > [Vor. XXXVI. 
of which are intense: purple red; the inner are yellow, and the 
anthers white. The snow-white petals of .S. sze//arzs are beset 
with ‘purple. dots and adorned with two orange-yellow spots. 
S. aspera and S. bxyoides are white, with numerous shining 
yellow dots. S. aizoides has large golden-yellow flowers, marked 
with numerous orange-red: dots; the nectaries and anthers are 
also yellow. This is the most conspicuous species of the genus 
and attracts 126 insects. S, oppositifolia has the honey more 
deeply concealed and is carmine or ‘purple, and is diligently 
visited by butterflies. S. Azreu/us, of Labrador, is bright yellow 
with scarlet spots. In S. michauxii the three largest white 
petals have a pair of yellow spots at the base, but the two smaller 
are unspotted. The petals of S. geum are white, with a yellow 
spot at the base and several smaller purplish spots in the middle. 
As evidence that these markings are pleasing to Diptera, Müller 
states that he saw many specimens of two drone flies, Sphegina 
clunipes and Pelecocera scevoides, before sucking honey or eating 
pollen, poising before the dotted flowers of S. rotundifolia as if 
delighted by their appearance. 
In his AZgeub/umen Müller has tabulated his observations 
upon the relations of Diptera to the different colors of flowers. 
Most anthophilous species and families of flies made a much 
larger number of visits to white and yellow than to red and blue 
flowers. The Bombylidez, which are suctorial only, showed a 
preference for red and blue to white and yellow in the proportion 
of 75 to 25; and the genera Volucella and Rhingia, of the 
Syrphidz, showed a similar inclination in the proportion of 7744, 
to 22,5. The less specialized Diptera were by far the most 
= common on white and yellow; but as the proboscis increased 
in length and the species confined themselves more strictly to 
flowers, the percentage of visits to red and blue flowers increased 
from 14,1; in the Muscidz to 294, in the Syrphide, and to 75 
in the Bombylidz. The AEA as flower visitors surpass all 
other Diptera, both in numbers and importance. The percentage 
of visits to yellow and white was 69,5, and to red and blue 
flowers was 2945. The species marked yellow, whether short 
or long tongued, were two to three tioesashbamant t ae white 
Meg cnn h > flov None of 

