THE BLACK FLY OF CITRUS. 35 
after molting, but are pushed forth within the first 10 minutes. 
The individuals are flat at first and at the end of 15 minutes they 
become distended, with the numerous spines standing out con- 
spicuously. The time for complete coloration, i. e., until the shiny 
black color so characteristic of this stage is reached, is from one to 
one and one-half hours. 
The shape is distinctly ovate in outline, the anterior being the 
smaller end. The insect is decidedly convex, with a prominent ridge, 
and is covered with numerous long, stout, conspicuous spines. 
The sexes are readily distinguished, the female pupse being almost 
twice the size of the males. Furthermore, a white wax is secreted 
around the margins of the body, the males usually secreting notice- 
ably more than the females. 
The duration of the pupal period is very irregular and ranges from 
16 to 80 days. Out of doors the maximum time that has been recorded 
is 48 days. 
The mortality in this stage is not as great as in the preceding 
stages, only 28 out of 268 individuals, or little more than 10 per 
cent, dying. 
In all the larval instars and in the pupal as well, shortly after the 
molting, it has been repeatedly noted that drops of a clear, more or 
less viscous fluid appear at the ends of practically all the spines. No 
openings have been noted at the ends of these spines after the insects 
have become fully colored, and they may only function for a short 
time and close, though this would seem to be a rather unusual con- 
dition. In some of the members of the genus Aleurocanthus the 
spines are distinctly open and in the genus Siphoninus the ilquid has 
been seen actually flowing from these openings. 
In the larval and pupal stages varying amounts of honeydew are 
excreted through the vasiform orifice, some colonies of individuals 
secreting more than others. The amount of honeydew excreted 
depends upon the rate at which the insects are feeding. The honey- 
dew falls on the leaves below the infested ones and soon sooty molds, 
fungi of the genus Meliola, begin growing on it. The heavy growth 
of the sooty molds on upper surfaces of the leaves, coupled with an 
abundance of A. woglumi individuals in various stages of development 
on the under surfaces, doubtless seriously interferes with the normal 
functioning of the leaves. (See Pis. V and VI.) Further, this 
double infestation may be so severe as to render leaves practically 
worthless to a tree and thus seriously interfere with its vigor. But 
infestations of A. woglumi are not necessarily accompanied by heavy 
growths of sooty mold, and the writers have found trees practically 
free from this insect and yet covered with heavy growths of these 
molds. In such instances the trees were usually badly infested with 
