42 BULLETIN 885, U. S. DEPAKTMENT OF AGKICULTUEE. 
with a number of long, slightly curved hairs, those near the tip being the longest. Penis: 
as long as claspers, yellowish, and almost straight. (PI. XI, E. ) (Forewing, PL XI, K.) 
Described from females, males, and pupa cases in balsam mounts 
and pupa cases and eggs on the leaves. 
It might not be out of place to discuss here the appearance of the 
spines during the period immediately after molting. As indicated on 
p. 35 there are seen on the spines shortly after molting drops of some 
material, apparently secreted by the spines, which is not seen after 
the spines have become fully developed and hardened. While we 
have available no fixed material and are, therefore, unable to make 
a study of the development of these spines, some information is 
obtainable from the material in hand which may throw light on the 
origin of this secretion. 
Immediately after the molt the spines may be seen to consist of a 
distinct outer collar or sheath of about the thickness of the base of 
the fully formed spine and a central acute portion much narrower in 
diameter protruding from it. This can be traced through the center 
of the sheath and some distance beyond its base (PL XI, B). In 
others this outer sheath is more extended, as is also the central core. 
Here we are unable in the available material to trace the central 
core beyond the base of the sheath, although it is distinctly traceable 
within the sheath. (Pi. XI, C.) In somewhat later specimens 
the spines have reached their full length and we are unable to trace 
the core through the center of the sheath. Moreover, the portion of 
the core which extends beyond the sheath is much greater in diame- 
ter than in the specimens just discussed, although the line of de- 
marcation is visible (PI. XI, D). In somewhat later specimens in 
which the spines have begun to change color we are unable to locate 
any trace of this former division. 
SEASONAL HISTORY. 
From a study of the life-history charts it is evident that the life 
history is not clear-cut and that under conditions that obtain in the 
laboratory there is a constant lagging behind in some individuals 
which becomes most pronounced in the pupal stage. On the basis of 
the maximum and minimum times for the completion of the life 
cycle from egg to adult there is the possibility of from three to six 
generations per year with all sorts of overlapping of generations 
even from the same colony of individuals. Thus a seasonal history 
of Aleurocanthus woglumi would resemble somewhat that of the 
asexual generations of some of the plant-lice. 
But another factor comes into play and that is the wide difference 
in the rainfall of wet and dry seasons in the Canal Zone as Table VII 
shows. This table is for the period during which the work given in 
this report was done. It is for the Pacific section and is based on 
