174 
them no lunger. They resemble the mealy bugs closely when young, 
but can be recognized by a few structural differences. The older bugs 
move but very little. The male has not been reared and the species 
carefully enough studied at present to speak further of it. 
A much more distant ally is Aleyrodes, which Prof. Oomstock 
classifies under the succeeding family by having two-jointed tarsi and 
four wings. The species that has been the most troublesome in the 
greenhouse the past year is what Dr. Packard determines for us as 
probably Aleyrodes vaporarium Westwood. Specimens have bred the 
most extensively on Ageratum mexicanum and Abutilon marmarophyl- 
lum, but a little later also bred quite as well on i>otted roses, geraniums, 
and Coleus. Our florist says that a few years ago they made the green 
foliage of the roses quite white after the plants had been set out in beds 
for the summer. A lady who lives near Detroit sent me the same 
insect on Salvia leaves, and Dr. Packard, in his report for 1870, speaks 
of them on fuchsias and as occurring in great abundance on the tomato 
in September. The species in the greenhouse is much the most com- 
mon through the last of the winter months and through the spring 
until the plants are taken out of doors for the summer. 
The eggs of this species are glued to the under side of the leaves. 
They are only about .25 mra in length, and when seen by the lens look 
like oblong cone-shaped galls. They are fastened perpendicularly to the 
leaf, and resemble a long, slender, pointed bird's egg fastened at the large 
end. On the Ageratum the leaves are so hairy that the female usually 
leaves only one egg in a place, but on Abutilon and rose leaves I have 
counted as high as 17 deposited in rapid succession inside of an area 
not greater than 1.5 mm in diameter and still none of them touching 
each other. The eggs when first deposited are green like the leaf, but 
in three days they turn a metallic blue-black. Eight days later the 
shining shell is burst and the young larvae scatter over the leaf and 
begin to feed. They were seldom seen traveling after the first few days 
of their larval life, unless a leaf on which they are located became 
wilted and no longer yielded a supply of food. They became perma- 
nently located and passed through the pupa stage with few perceptible 
external changes. About three weeks is required to pass through the 
larval stage and about one week in the pupa stage. When we add the 
pleveu days in the egg to this, we have from four to five weeks as the 
period for the development of each brood. They breed so fast and 
become so abundant at times that they would do great harm were they 
not so exceedingly minute. Last spring they nearly killed our Age- 
ratum plants by puncturing the leaves so thoroughly that the leaves 
which glazed with sap and this started a soot fungus, Fumago vagans, 
which always follows such work. 
In conclusion, we must acknowledge that there is still much to be 
learned regarding the species treated of in this paper. The vision, 
seen in the study of these few, reveals that there is a large and inter- 
