172 TRANSACTIONS OF THE ILLINOIS 



changed it to the name we have here given. It is evidently very closely 

 allied to the preceding, yet appears to be distinct. It is a large species, 

 although smaller than L. dentalus, and lives on the branches and twigs of 

 various kinds of willows, clustering* together on the under side, often in 

 great numbers. The winged individuals appear about the first of October. 

 The body measures about one-tenth of an inch in length ; to the tips of 

 the wings about two-tenths. They are without the conical projectioi:, or 

 stylet, found in most of the species already described, at the tip of the 

 abdomen ; the honey-tubes are much shortened. The body is black, and 

 the abdomen is without the dots which are so often present in this genus. 

 The wings are pellucid, but the veins are yellowish, as are the legs, tlie 

 honey-tubes and the first joint of the antennae. As in the preceding 

 species, when crushed, it gives out a stain of reddish or deep orange color, 

 showing such a strong resemblance to that species in this respect, as well 

 as in its habits, that, were it not for the marked differences in coloration 

 and size, we should not hesitate to consider them as but varieties of one 

 species, which further evidence may yet prove to be the case. 



CjO. Lachnus saiicelts, Fitch. 



Under this name Dr. Fitch describes another species which is found 

 on the willow. It is smaller than Harris' species, and, like it, appears also 

 to be without spots on the abdomen, and in all probability is but a 

 variety of that species. Black; tibise and base of the antennae pale; 

 base and costal margin of the fore wings yellowish-white. Length, .08 

 inch. Resides on the succulent twigs. 



51. Lac/inus carycB, Harr. The Hickory Plant-louse. 



This is the Aphis caryce of Harris, and is found on the pig-nut 

 hickory (Carya porcina), clustered on the under side of the limbs and 

 twigs during the summer. It is perhaps our largest species, measuring 

 one-fourth of an inch to the tip of the abdomen, and above four-tenths 

 to the tips of the wings. The honey-tubes are quite short, and there is 

 no stylet at the end of the abdomen. The body appears to be slightly 

 powdered or pruinose ; and the abdomen is marked with four transverse 

 rows of black dots ; the upper side of the throax and the veins of the 

 wings are black, as are also the tibiae and tarsi ; the thighs are reddish 

 brown ; the antennae are dark and clothed with black hairs. 



52. Lachniis strobi. Fitch. The White Pine Lachnus. 



Found in colonies on the ends of the branches of the white pine, 

 and probably also on other pines, puncturing them and extracting their 

 juices ; giving to the bark upon which they are located a peculiar black 

 appearance. Tlie winged individuals measure two-tenths of an inch to 

 the tips of the wings ; they are black, hairy and sometimes slightly dusted 

 over with a white powder, with a row of white spots along the middle of 

 the abdomen; the thighs are pale yellowish at base; the fore wings 

 hyaline with black veins, the third being exceedingly slender. The 



