194 INSECTS INJURIOUS TO VEGETATION. 



which remains to be described; — it measures about half an 

 inch from the tip of the horn to the end of the body; the male 

 is blackish above, with a long yellow spot on each side of the 

 back ; and the female is ash-colored, and without spots. While 

 on the trees, these insects, though perfectly still, are not unem- 

 ployed; but puncture the bark with their sharp and slender 

 beaks, and imbibe the sap for nourishment. The female also 

 appears to commit her eggs to the protection of the tree, being 

 furnished with a piercer beneath the extremity of her body, 

 with which to make suitable perforations in the branches. As 

 I have never seen the young on these trees, I presume that, as 

 soon as they are hatched, they make their way to the ground, 

 and remain under the surface of the soil, sucking the sap from 

 the roots of plants, until they are about to enter upon their 

 last period of existence, when they crawl up the trunks of the 

 trees, throw off" their coats, and appear in the perfect or winged 

 state. From the great numbers of these tree-hoppers which 

 exist in certain seasons, the locust-trees undoubtedly suffer 

 much, not only in consequence of the quantity of sap abstracted 

 from their branches, but from the numerous punctures made 

 by the insects in obtaining it and in laying their eggs. 



The oak-tree is attacked by another species, the white-lined 

 tree-hopper (M. univittata)^ which may be found upon it during 

 the month of July. It is about four tenths of an inch in length ; 

 the thorax is brown, has a short obtuse horn extending ob- 

 liquely upwards from its fore part, and there is a white line on 

 the back, extending from the top of the horn to the hinder 

 extremity. 



The common creeper [Ampelopsis quinquefolia) is inhabited 

 by a tree-hopper, which has an oblong square and thin eleva- 

 tion or crest on the middle of the thorax. Its body is usually 

 of a reddish ash-color, and the thorax is ornamented with three 

 reddish brown bands, one of which is above the head and ex- 

 tends transversely between the lateral projecting angles of the 

 thorax, the second is a short and oblique line on each side of 

 the front part of the crest, and the third is also oblique, and 

 begins on the outer edge of the thorax, and passes obliquely 



