BUGS. 
37 
of numerous tiny creatures of a green or brown 
color to match the color of the plant on which 
they live. A further observation will disclose the 
fact that these tiny creatures are not all alike in 
Fig. 20.—Willow Aphis. 
shape or size, and also that some have wings, while 
others are destitute of these organs. These are 
aphides or plant-lice. They abound almost every¬ 
where, and on this account as well as on account of 
their wonderful powers of propagation, they deserve 
careful study. 
All that is needed for school study of the aphis 
is a good simple microscope or a magnifying glass 
with which to observe them. 
The drawings are very much 
enlarged and the little line 
beside each indicates the 
true size of the insect. 
It is beyond the limits of 
this book to deal at all ex¬ 
tensively with these very 
interesting creatures. Their 
life-history is exceedingly 
complex. There are two forms of plant-lice, the 
