406 AN INTRODUCTION TO ENTOMOLOGY 



forms (Fig. 472), of which about thirty species have been found 

 in our fauna. They Hve chiefly on oaks, hickories, basswood, and 

 other forest trees. The adults generally rest singly on the limbs 

 and branches of the trees; they are strong flyers and are difficult to 

 capture. The immature forms keep together in small groups. 



Figure 473 represents a front view of several membracids in our 

 collection. 



Family CICADELLID^* 



The Leaf-Hoppers 



This family is a very large one, and it is also of considerable 



economic importance; for it includes a niimber of species that are 



very injurious to cultivated plants. The members of it are of small 



or moderate size. The antennas are inserted in front of 



and between the eyes; the pronotum is not prolonged 



above the abdomen; and the hind tibiae are nearly 



or quite as long as the abdomen, curved, and 



armed with a row of spines on each margin. The form 



and armature of the hind tibiae are the most salient 



characters of this family. The form of the body is 



jl i commonly long and slender, often spindle-shaped ; but 



p. some are plump. 



^%elis exiti- These insects are able to leap powerfully; and, as 

 osus. they are more often found on the leaves of herbage 



and on grass than elsewhere, they have been named leaf-hoppers. 

 They infest a great variety of plants; some of them are important 

 pests in gardens, orchards, and vineyards; but they are most destruc- 

 tive as pests of grains and grasses. Although this is true, much 

 less attention has been paid to injuries caused by them to grains 

 and grasses than to those inflicted upon vineyards and rose bushes. 

 More than seven hundred species, representing about seventy 

 genera, have been found in theUnited States and Canada. Among the 

 more important members of the family from an economic standpoint 

 are the following. 



The destructive leaf-hopper, Euscelis exitidsus, which is repre- 

 sented, greatly enlarged, in Figure 474, sometimes infests winter 

 wheat to a serious extent. It is a widely distributed species, its 

 range including nearly the whole of the United States. It is a 

 small, active, brownish insect, which measures with its wings folded 

 about 5 mm. in length. It injures grass or grain by piercing the 

 midrib of the leaf and sucking the juices from it. 



The grape-vine leaf-hopper, Erythroneura conies, is a well-known 

 pest which infests the leaves of grape, in all parts of this country 

 where this vine is grown. It is a little more than 3 mm. in length, 

 and has the back and wings marked in a peculiar manner with yellow 

 and red. In the winter the darker markings are a dark orange-red, 

 but after feeding has been resumed for a short time in the spring 

 they change to a light lemon-yellow. The darker markings on the 



*Tliis family has been commonly known as the Jassidae, but Cicadellidae is the 

 older name. 



