27 
[987] 
inverted umbrella under an infested apple tree, at this period, you 
will soon see the little white crawling points upon it, being the 
more easily detected from their contrast with the black back 
ground. They can also be seen upon the grass or other objects 
under the tree by examining with a lens. They will uniformly 
be found further from the tree on the side towards which the wind 
is blowing than on the other. I have also found them thickly 
sprinkled upon the upper surface of cob-webs which happened to 
be spread over the grass at the distance of two or three rods from 
the tree. Being caught on the web, it was evident they could not 
have crawled there, but that they must have fallen there from 
above. 
An interesting query here suggested itself as to the degree of 
tenacity with which these insects adhere to the tree at this period, 
and how strong a wind it requires to remove them. To deter¬ 
mine r this point I experimented by blowing upon them with my 
mouth, with different degrees of intensity. I found that a pretty 
strong current of wind did not disturb them, provided it was 
steady and uniform, but that a short, sharp puff readily dislodged 
them. At one time, during my examination, the wind arose and 
blew a pretty stiff breeze, and I could feel it sweep over the sur¬ 
face I was examining with considerable force; yet in only a very 
few instances could I perceive that any of the Coccids were blown 
off; and yet actual observation showed that the ground beneath 
was thickly sprinkled with them. The query arises whether these 
creatures may not have an instinct to loosen their hold upon the 
tree, irrespective of the force of the wind, for the purpose of dis¬ 
semination. This may seem improbable, but it is no more won¬ 
derful than many of the instincts of insects. 
A still more important question is, how far they can be trans¬ 
ported by the wind. This will depend very much, of course, upon 
the force with which the wind may happen to be blowing, at any 
given locality, at the hatching period. At the time I made part 
of my observations, last spring, there was a pretty fresh breeze 
blowing, but I did not detect any Coccids upon the ground beyond 
about three rods from the extreme branches of the trees. Never¬ 
theless, some of them may have been carried farther, for it must 
be borne in mind that it is not an easy thing to find such minute 
objects upon the ground, except where they are numerously dis- 
