124 [Assembly, 



one-sixteenth of an inch long, with a tuft-like down attached to 

 the end of the body. They are found in large numbers in the woods, 

 but only on the beech. The limbs are so thickly covered with 

 them that in their continual swaying motions back and forth they 

 all keep time. Underneath, the leaves and ground are covered 

 with a blue or drab-colored substance, undoubtedly the offal from 

 them." 



The insect is one of the aphides (Aphididw, commonly known 

 as plant-lice), having the scientific appellation of Pemphigus imbri- 

 cator. Popularly, it is known as the beech-tree blight. 



It was first described by Dr. Fitch in 1851, in the Fourth Annual 

 Report of the New York State Cabinet of Natural History, and 

 as that publication is almost inaccessible, the description is here- 

 with transcribed : 



"Eriosoma imbricator. Black; three last segments of the abdo- 

 men blue-pruinose ; stigma brown ; longitudinal nerve and a line 

 on the middle of the inner margin black. Female (?) winged ; 

 abdomen fulvous, with a black spot on the disk ; legs pallid. Larva 

 pallid, with two fuscous dorsal stripes; posterior half of the abdo- 

 men covered with a tuft of cotton-like down, from which proceed 

 two longer and coarser filaments. Length, 0.22 inch. On the 

 under side of the branches of the beech tree, covered with snow- 

 white down. On the slightest jar of the branch, a shower of tiny 

 drops of a water-like fluid falls from these insects." 



This species has been noticed by but few of our writers. 

 Dr. Thomas, in the Eighth Report on the Insects of Illinois (p. 139), 

 refers to it, quoting from Dr. Fitch, and assigns it place in the 

 genus Schizoneura. It does not, however, belong to this genus, 

 as its third discal vein is not forked. Dr. Packard, in his Insects 

 Injurious to Forest and Shade Trees (p. 131), cites it among beech 

 insects, also designating it as a Schizoneura. 



A peculiar feature of this insect and of its allied species, which 

 so often draws attention to them, is the white substance in which 

 they are enveloped, resembling threads of cotton or wool, and 

 which has given to them the name of " woolly aphides." It 

 appears in the form of threads or fibres, which are sometimes 

 long and flattened, as in the beech-blight, and sometimes in the 

 form of a fine powder. The substance is secreted by glandular 

 organs in the abdomen and thorax, and is of a peculiar character, 



