HICKORY, LEAVES— LITTLE HICKORY APHIS. 165 



most coriimon upon the leaves of the hickory may be distinguished 

 by the following characters. 



The LITTLE Hickory Aphis (Aphis Caryella) is pale yellow with white antennae 

 ■which are alternated with Ijlack rings, the wings transparent and wiihout spots, 

 their veins slender and pale yellow, the legs yellowish white to their ends. Length 

 0.12 to the tips of the wings. The abdomen is depressed, egg-shaped, its apex 

 slightly narrowed and elongated. The antennae are longer than the body, taperingj 

 seven -jointed; two basal joints as broad as long, twice the diameter of the following 

 Joints; third joint longest, slightly thicker towards its base; fourth and fifth joint* 

 rather shorter than the third, cylindric; two last joints together about equaling the 

 fifth in length ; the sixth swelled at its tip into a long oval knob, the seventh mors 

 slender but not capillary, shorter than the sixth; a broad black band at the apex of 

 the third and each of the three following joints. First vein of the fore wings straiglit 

 and almost transverse; second vein bent near its base, running first towards the apei 

 and then turning rather abruptly and continuing straight to the inner margin, more 

 than twice as far from the first at tip as at base ; third vein arising from the stigm» 

 near its anterior end, and not from the rib- vein forward of the stigma, as it does ia 

 the aphides generally, except those pertaining to this group, its base and its apex 

 about the same distance from the second vein that this is from thefirst, forking rather 

 forward of its middle, strongly bent at this point, and from hence to its tip paralld 

 with the third vein -of but slightly diverging from it, its tip a third nearer that of the 

 third vein than this is to tlie second; second fork nearer the fourth vein at tip than 

 to the first fork, the triangular cell between it and the first fork with its three sidee 

 equal; fourth vein short and often nearly abortive, shoiter than the second fork, 

 equally curved through its whole length, its tip much nearer that of the rib-veim 

 than that of the second fork; rib-vein very slightly diverging from the margin from 

 ttie base to the stigma, curved from thence to its tip. Stigma oval, about twice a« 

 long as wide, watery, sometimes tinged with yellowish. A variety has the sterna 

 dusky at its tip. Another variety {costalis) has the rib-vein coal black interrupted 

 with whitish towards the stigma, which is dusky, and black at each end. 



In addition to the species now described, four others occur 

 upon tlie under surface of the leaves of the hickory and walnut, 

 similar to it in size, form and genenil color, and as some of these 

 are frequently met with upon the same leaves with the preceding 

 they might be suspected to be mere varieties. Their spots and 

 marks, however, are so clear and definite and the veins of their 

 wings are so dissimilar that we are ©bliged to regard them as dis- 

 tinct species. They may be named and briefly characterized as 

 follows : 



The little dotted-winoed aphis (Jl. punctatella) is much like the preceding 

 in the color of its body, antenofe and wings, but has black feet and a black dot on the 

 base and another on the apex ef each of the veins of the fore wings; the stigma i« 

 salt- white with a brown streak at each end; the second vein is wavy and at its tip is 



