STATE HORTICULTURAL SOCIETY. 



ni 



47. Aphis populifolicE, Fitch. The Poplar-leaf Aphis. 



Inhabits the under side of the Populus grandidentata. Of a chestnut - 

 brown color, mealy; legs hairy, black, pale brown above the knees; 

 veins of the fore wings brown, stigma smoky-yellow, margined with black ; 

 black with two rows of impressed, squarish, fuscous spots ; on each side 

 two rows of impressed dots ; honey-tubes equaling a third of the distance 

 to the tip. Length, 0.22 inch. 



Genus Lachnus. 



This genus was established by Illiger, to receive those spe^cies which 

 agree in general appearance with the species of Aphis, but have the 

 honey-tubes much abbreviated or reduced to mere tubercles. In addition 

 to this difference, the antennae are only six-jointed, usually shorter than 

 the body, and sometimes thread-like or filiform. The beak is usually 

 longer than in the previous genus. They usually inhabit the twigs and 

 small limbs rather than the leaves, and, according to Dr. LeBaron, gen- 

 erally have the abdomen dotted, though there are exceptions to this rule. 

 The species are far less numerous than in the preceding genus, and, so far 

 as I am aware, have never infested the fruit trees in this country. 



48. Lachnus dentatus, LeB. The Spotted Willow Aphis. 



I As Dr. LeBaron — who first named this 



species — has already described it in his 

 Second Report, it will be unnecessary 

 for me to do more than simply mention 

 some of the chief characters as there given, 

 as I have not studied the species. 



It is found in October and November, 

 in colonies, on the under side of the 

 branches of the gray willow; and occa- 

 sionally, but apparently accidentally, on 

 the trunks of small nursery apple trees. 

 The winged individuals measure about 

 one-sixth of an inch long; the wings expanding about half an 

 inch. Black ; abdomen dark ash color, with six transverse rows of black 

 dots. Antennae as long as the head and throax. Front wings with a 

 very long stigma ; the third vein with two forks, as usual in this genus as 

 well as the preceding. Honey-tubes reduced to mere tubercles. Thighs 

 dark honey-yellow, broadly tipped with black ; tibiai dusky reddish at 

 the base. The dots on the abdomen are very distinct in the full grown 

 individuals; the intermediate rows have six dots in a row. Just behind 

 the middle of the abdomen, and occupying the place of the two middle 

 dots in the fourth row, is usually a somewhat conspicuous, black, conical 

 protuberance. When crushed, they stain the fingers red. 



49. Lachnus salicicola, Uhler. The Plant-louse of the Willow. 



This is the A. salicti of Harris, but as this specific name had already 

 been given by Schrank to a European species infesting the willow, Uhler 



Fig. 4- 



