174 



them no longer. 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 uuich more distant ally is Aleyrodes, which Prof. Comstock 

 classihes 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 AhutUon marmarojphyl- 

 lum, but a little later also bred quite as well on potted 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 mc the same 

 insect on Salvia leaves, and Dr. Packard, in his report for 1870, speaks 

 of them on fuchsias and as occurring iu 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'"™ iu 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 iu rapid succession inside of an-area 

 not greater than 1.5'"'" 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 Ave add the 

 eleven 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, Fnmago 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- 



