Packard.] 
mSECTS OP THE GARDEN. 
41 
species, are greatly increased. We know from personal ob¬ 
servation that these male scale insects do travel far from the 
trees on which their partners occur. 
This leads us to regard this almost unnatural activity of 
the male scale insect as tending to prevent too close in-and-in 
breeding in the species. Nature in her wise and prudent 
forethought thus, instead of confining the sexes to one tree, 
so that cousins intermarry and the stock deteriorates, scat- 
FlG. 32. 
ters these two-winged atoms, bearing them along on the wings 
of the wind and landing them in other groves and orchards, 
where they may intermarry with different races, and thus the 
species be restrained within the proper limits. Here we have 
another cause by which these sexual differences may have 
been produced. 
Any one who has noticed these female scale insects clus¬ 
tering on an orange or ivy or oleander leaf, knows how much 
their form varies with that of the surface to which they are 
9 
