STATE HORTICULTURAL SOCIETY. 193 



70. Eriosoma guerci, Fitch. The "Oak Blight," or Woolly Aphis of the 



Oak. 



This species is found in the northern part of this State, upon oak 

 limbs. Fitch says it is very similar to another species found on the bass- 

 wood. The winged individuals are black throughout, slightly dusted 

 over with an ash-gray powder. The fore wings are clear and transparent : 

 the stigma is dusky, the rib-veins black, and the third discoidal vein with 

 the basal portion abortive nearly or quite to the fork. The length to the 

 tip of the wings is (o.i6) a little over one-eighth of an inch. 



71. Eriosoma tessellata, Fitch. The Alder Blight. 



m 



This species is found on the under side of the branches of the alder 

 {Almis rubra), crowded together and concealed beneath a covering of 

 snow-white down. Wingless individuals, dull bluish black; the back of 

 the segments are marked with strongly impressed lines, and covered with 

 white down in square, checker-like spots. Length to the tip of the abdo- 

 men, o. 16 inch. 



72. Eriosoma iinbricator, Fitch. The Beech-tree Blight. 



This species occurs on the under side of the branches of the beech, 

 covered with a coating of white down; and, according to Dr. Fitch, 

 from whose report the description of this, the preceding and following 

 species is copied, when the branch on which they are situated is jarred a 

 shower of tiny drops of a water-like fluid falls from these insects. It is 

 possible it is identical with the European Beech Blight {E. fagi, Linn.) 



Black; three last segments of the abdon)en, blue-primrose: longitu- 

 dinal vein, and a line on the middle of the inner margin, black. Winged 

 females have the abdomen yellowish, with a black spot on the disk ; legs, 

 pale. Larva, pale, with two fuscous dorsal stripes ; posterior half of the 

 abdomen covered with a tuft of cottony down, from which proceed two 

 longer and coarser filaments. Length to tip of wings, 0.22 inch. 



73. Eriosot?ia strobi, Fitch. The Pine-tree Blight. 



Common on the branches of the white pine, giving to the bark of 

 infested trees a peculiar black appearance. Black, pubescent, somewhat 

 powdered ; a dorsal row of meal-like spots ; fore wings with the costal 

 margin, the apical, and two inner basal veins, black. Length, 0.20 inch. 

 Belongs, according to Fitch, to a distinct genus intermediate between 

 Eriosoma and Lachnus. 



Genus PEMPHIGUS. 



The species belonging to this genus are distinguished by the absence 

 of honey-tubes from the abdomen ; by the third discoidal or branch vein 

 of the fore wings being simple without fork or veinlet, and often more or 



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