32 
K 
lives during the summer upon the leaves, stem or trunk of a plant, 
when winter approaches, moves down to the root, where the individuals 
of the new generation, assume a somewhat different appearance and 
different habits from their aerial predecessors, the difference being 
sometimes so great as to cause them to be placed in entirely differ¬ 
ent groups. 
And it is even possible that some which are found during the summer 
on annuals pass in autumn to the roots of perennial plants, though 
this has not yet been positively ascertained. 
If we examine the roots of grasses and various other plants in 
the latter part of autumn or early in the winter, we will find now and 
then a number of pale creamy-white plant-lice clinging to them. These 
are very similar in appearance, short thick and convex ; with very short 
antennae, consisting of five or six joints ; the eyes minute or apparently 
wanting ; and as a matter of course without wings. Sometimes others 
a little more active, of an ashy-purple color are found with them. 
These differ from the others not only in color but are somewhat larger, 
have longer antennae consisting of six or seven joints ; eyes distinct; 
wingless. These subterranean species, on account of various minute 
differences observed between them, have not only been described 
as different specifically, but have been grouped into several different 
genera, the number and relative length of the joints of the antennae, 
being one of the chief characters selected for this purpose. 
While there are undoubtedly some species which are permanently subter¬ 
ranean, I am pretty well satisfied from my observation and study 
of these insects that a large portion of these root feeding species are 
but dimorphic forms of aerial species found upon plants in the growing 
season of the year. While in this condition, development appears to 
be retarded, the larva appear to remain in this state probably as long 
as the rigor of the season is unfavorable to development; and I have 
even observed that they may be caught in the pupa state, with the 
wing-pads formed and remain for an unusually long time in this con¬ 
dition, many of them possibly never acquiring full wings. 
From observations made on several species I am now pretty well 
satisfied that a large portion of these pale, cream colored subterranean 
species, with short five-jointed antennae, are larvae; the bluish speci¬ 
mens with longer and more numerous jointed antennae are in a more 
advanced stage. I will not attempt to give my reason for this opin¬ 
ion here, as T would have to enter into details interesting only to en¬ 
tomologists. 
If I am correct in this opinion, which Buckton, the latest English 
authority on these insects, appears to have entertained, at least in part, 
it may ultimately assist us in tracing out a portion of their life his¬ 
tory, which is yet involved in mystery. 
That many species, like the apple-tree plant-louse, deposit eggs in 
the fall and pass the winter in this state is well known, and it is quite 
probable that most of the tree-inhabiting species adopt this method, 
though some, as the wooly-aphis of the same tree, are known to pene¬ 
trate to the roots. 
