FIRST series: pemphigus ACERlPOLIt RILEY. 13 



mothers, slowly moving about, all of which would have had to crawl 

 5 to 10 feet to reach the nearest branches. Young larvse were not 

 yet present, though the buds were just swelling. 



May 11^ 1906.-— To-daj I saw near Rosslyn, Va., a few young stem- 

 mothers on leaves of lower branches of maples stationed near the 

 base of the midrib on the underside of the leaves. Two of them were 

 already fully grown and completely covered with a large amount of 

 woolly secretion, irregidarly interspersed with rather long and more 

 or less curly or wavy white threads. These two females deposited a 

 few larvse till the day following. 



May 18, 1906. — Found at Rosslyn, in the same locality as above, six 

 of the stem-mothers on one of the maples. With one of them were 

 75 and with another one over 100 larva^, which were already of two 

 stages and of a pale orange color. The smaller larva3 had a brush 

 of wdiite secretions at the end of the body, whereas the whole dorsum 

 of the larger or older larvae was covered with long, white wool, inter- 

 spersed with twine-like, wavy strands. 



June 6, 1906. — A lot of maple leaves badly infested with Pemphi- 

 gus acerifolii were received to-day from Fredericksburg, Va. Among 

 the aphides were quite a number of migrants, some of which were 

 placed on leaves of a potted alder and soon settled on the underside 

 of these leaves. On examining this tree in the afternoon of the 

 next day I found that one of the migrants had deposited a consider- 

 able number of larvae, which soon after were seen traveling up and 

 down the stem. 



Jmie 10, 1906. — Discovered to-day four colonies of Pemphigus 

 acerifolii on leaves of maple near the Chain Bridge, District of 

 Columbia. The infested leaves were almost folded, both halves bend- 

 ing down from the midrib. Inside of these folds were numbers of 

 pupae which at the anal end were provided with about 12 rather 

 stout, twine-like, and somewhat wavy or curly white filaments, about 

 3 or 4 times the length of the body, spreading out fanlike, inter- 

 mixed at their bases with shorter, fine wool or secretion. In the 

 immediate neighborhood numbers of migrants were already found 

 on the leaves of alders accompanied by a brood of their larvae, 

 besides numerous colonies of larvae on branches and stems. 



June 18, 1906. — A large colony of larvae from migrants of Pemphi- 

 gus acerifolii, which had settled on the stem of a potted alder, was 

 greatly reduced by pupae of (Nahis) Pagasa fusca Stein, which fed 

 on the aphides. 



Ju7ie 26, 1906. — Observed to-day numbers of migrants from maple 

 on the imderside of leaves of alders near the Chain Bridge, District 

 of Columbia. Many of them were already dead, though all others, 

 still living, were empty and shrunken. Two of the migrants, alive 

 and active, were surrounded by numerous larvae, and still depositing. 



