LEAF HOPPERS INJURIOUS TO CEEEAL AND FOEAGE CEOPS 21 



There is not much to be added to the discussion of the general 

 control, as this species is one of the most widely distributed and is 

 open to every remedy which has been advised for the leaf hoppers 

 in general. The fact that it is primarily a grass insect, and that it 

 attacks wheat, oats, and other grains incidentally, makes it possible 

 to reduce its injuries to grain by attention to the adjacent fields. 

 The burning of grass along the sides of the field, in fence corners, 

 or along roadsides would in a large degree protect wheat fields from 

 the fall migrations. The species is readily caught in the hopper- 

 dozer, and in pastures or permanent meadows where burning is 

 not considered desirable this or the application of an insecticide by 

 spraying is probably the most desirable control measure. 



THE BLACK-FACED LEAF HOPPER 



The black-faced leaf hopper, Thamnotettix nigrifrons Forbes, 

 is an abundant and very widely distributed species, occurring in a 

 number of variations, so it has received several technical names. It 

 was first described by Forbes (7) from specimens found infesting 

 wheat and oats, but neither details of life history nor mention of its 

 habits or distribution were given. 



DISTRIBUTION 



The species is distributed over a large part if not the entire north- 

 ern and eastern part of the United States, having been found all the 

 way from New York to Georgia, and west to New Mexico. 



FOOD PLANTS 



Although this leaf hopper has a considerable range of food plants, 

 there is apparently a distinct preference for the annual grasses, such 

 as foxtail or panic grasses and others, but it migrates very readily 

 from these into wheat, oats, and other cereals and also occurs very 

 commonly in bluegrass and timothy, especially after the withering 

 of the annual grasses upon which it has fed earlier in the season. 

 On this account it is one of the most troublesome forms occurring in 

 fall wheat and oats, since it has developed in great numbers upon 

 early grasses and, with the failing of these as a food supply, is 

 forced to migrate, and this migration, timed with the appearance of 

 the young and succulent plants of wheat and oats, is directed to them 

 as the most attractive bait. 



DESCRIPTION AND LIFE-HISTORY NOTES 



The adults (fig. 5, a) are to be recognized by the rather short 

 vertex, the margins of which are plainly rounded, and especially by 

 a distinct row of black spots which lies next the border of the upper 

 part of the head and bends down alongside the eyes in front. Of 

 these spots, four are on the upper part between the ocelli, usually 

 one on each ocellus, and two on each side between the ocelli and the 

 bases of the antennae. Other spots may occur with greater or less 

 distinctness on the upper part of the head, but they are too variable 



