246 NATURAL HISTORY OF ARTHROPODS. 



more or less tinged with brown or yellow, and the veins are thick, brown, sometimes 

 clouded with brown each side, and the costal vein is whitish. It measures about two- 

 twelfths of an inch to the tip of wing-covers. This insect swarms in wheat-fields, 

 meadows, and low spots along the edges of oak woods, in spring and late summer. 

 It is reported to be very injurious to wheat and oats, as well as to the grasses in 

 various parts of the southern States ; but it is by no means confined to that region, for 

 I have secured specimens from all the Atlantic States south of New York, and even 

 from Colorado near the Rocky Mountains. 



Other forms, some of them very pretty, described by Mr. Say and others, belong 

 here ; but which we can now only mention by name. They are Thamnotettix clitel- 

 larius, T. seminudtts, T. kennicottii, Grypotes tergatus, G. unicolor, and the gray- 

 mixed or brown-spotted little hoppers with deltoid heads, belonging to Deltocephalus, 

 but described by Dr. Fitch under the genus Amblycephalus. 



One small assemblage of genera within this group yet remains to be mentioned, 

 deserving attention from the fact that some of the species swarm upon vines and other 

 productions of the garden and field, causing widespread injury and ruin by exhausting 

 the sap of the plants. One of these is the genus Erythroneura. It is 

 composed of quite small, very slender, spindle-shaped insects, with few 

 cells to the wing-covers, and these, four in number, are confined to the 

 tip. E. vitia is ivory yellow, marked with two lines on the vertex ; a band 

 across the back part of the pronotum, the scutellum, the wing-covers at 

 base, and a band across their middle are all bright crimson. Occasionally 

 FIG. zu.Ery- there are some red marks behind the middle band, and the tips are more 



throneuravitis. 



or less blackish. This species varies in an uncommon degree. It lays its 

 eggs in April and May upon the tender leaves of the vine, and by the middle of June 

 swarms in the perfect state upon the under-side of the leaves. It inhabits the Atlantic 

 region from Massachusetts to Georgia, and spreads west into the Mississippi valley. 



In the last sub-family of the Hornoptera we reach the Tettigonida. These are 

 mostly small or medium sized insects with long bodies, an expanded face upon which 

 the front is set as a prominent ridge, the antennae bristle-shaped, set upon thick basal 

 joints, and placed in a cavity beneath the rim of the vertex. The position of the 

 ocelli upon the vertex, instead of in front, will at once separate these from those of 

 the foregoing group. 



At the outset of this assemblage we find a few forms which by their plump pro- 

 portions are brought strongly in contrast with the general type of the group. One of 

 these, which might be mistaken for a Clastoptera, is the Pentkimia. Here the crown 

 of the head is broad, nearly quadrangular, and curves down bluntly over the face. It 

 has large triangular eyes, and ocelli placed pretty far forward. Most of the upper 

 surface is transversely wrinkled, and the wing-covers, excepting the disc of the corium, 

 are closely punctate. The face is moderately broad, somewhat covers the side of the 

 fore coxa?, and the hind shanks are much curved. Our native species, the P. ameri- 

 cana, is of a chestnut brown, sometimes very dark, or even pitch-black, with an 

 irregular whitish patch, enclosing two or three dark spots, on the membrane. When 

 fresh it is seen to be invested with bronze-colored pubescence upon the wing-covers 

 and base of the scutellum. Several marked varieties occur, one of w r hich has two red 

 dots on the black vertex and a spot of the same color on each outer angle of the pro- 

 thorax. It is about one fourth of an inch in length to the tip of the wing-covers ; and 

 it lives on the sugar maple in the northern States and Canada, but is found upon small 



