14 LIFE HISTORY OF THE ALDER BLIGHT APHIS. 



There were also numerous colonies of young larvae on the branches 

 and stems. 



May 28, 1911. — Found to-day one colony of Pem-pliigus acerifolii 

 on a leaf of maple near Kosslyn, Va., containing one stem-mother 

 and 135 of her progeny — mostly pupae, in various stages of develop- 

 ment — besides many quite small larvse, while the mother appeared 

 to be in a condition to deposit still more. 



SECOND SERIES: PEMPHIGUS TESSELLATA FITCH. 



Notwithstanding that the insect under this name had been known 

 to me since 1869 as having a range from Canada to Florida and as 

 far west as St. Louis, Mo., occurring upon native and foreign species 

 of alders, the first attempt to learn its life history was begun in 

 June, 1883, when young colonies had established themselves on 

 branches of different kinds of alders on the grounds of the Depart- 

 ment of Agriculture at Washington, D. C. The larvae were appar- 

 ently the progeny of migrants from maples nearby. They had 

 settled on the underside of the branches in groups of 4 to 8 speci- 

 mens, arranged in circles, with their heads toward the center. All 

 were covered with rather long, white secretion, so as to resemble 

 a rosette, or a single insect, reminding one strongly of some of the 

 aleyrodids. This secretion issues from 6 rows of transversely oval 

 and rather flat warts. 



Early in October of the same year some of the branches were 

 almost completely covered with colonies 12 or more inches in length. 

 Among the great number of apterous females were also many pupae 

 and large numbers of winged specimens. 



EXTRACTS FROM NOTES MADE AT THE TIME. 



April 28, 1897. — Observed again small colonies of larvae on alders 

 on the Agricultural grounds. All of them Avere densely covered with 

 a white and woolly secretion, intermixed with stout and curly threads. 

 They were closely packed and resembled colonies of large mealy- 

 bugs, arranged more or less in circles ; sometimes they were, however, 

 so much crowded that many were actually standing on their heads. 

 These larvae had apparently been hibernating since the previous fall. 



Septeraber 12, 1897. — Found large colonies of this insect on alders 

 at Cabin John, Mel., and among them numerous pupae and migrants. 

 The winged specimens were densely covered with long, white tufts 

 of secretion, which formed a dense mass on the dorsum and around 

 the end of the body, besides projecting in shaggy tufts above the 

 closed wings. This secretion was intermixed at the anal end of the 

 body with longer and stouter threads; along the sides of the abdomen 

 were rather long, delicate, and somewhat curly, erect tufts or 

 streamers, and also long and forwardly directed tufts on the thorax 



