30 



CIRCULAR 2 41, U. S. DEPARTMENT OF AGRICULTURE 



(7) in 1885, and there is a record in the Bureau of Entomology by 

 F. M. Webster, dated December 4, 1885, of its occurrence on wheat. 



There is little separation into distinct broods, and adults are found 

 throughout the season, probably because of the short period of de- 

 velopment of the young. In Texas adults have been abundant as early 

 as March 22. Webster gives a record of adults, confined on wheat 

 kept indoors, which deposited eggs on November 11. These hatched 

 November 27. A further note on the last-stage nymph on December 

 24 would indicate the passing nearly to adult stage within a period of 

 about six weeks under indoor conditions. With present data, it 

 seems impossible to determine definitely the number of generations 

 during a season except for individual localities. 



The adult insect (fig. 11) is of a light greenish -yellow color. The 

 head is marked very distinctly with black dots or spots arranged in 

 pairs; there are two round spots on the hind part of the vertex, a 

 pair of transverse spots a little in front of the middle, and another 



Figure 11. — The six-spotted leaf hopper (Cicadula 6-notata) : a, Adult, 

 X 10 ; ~b, face ; c, wing ; d, female genitalia ; e, male genitalia ; 

 f, nymph 



pair, also transverse, at the border between the vertex and the front. 

 The front is marked with black curved lines, and the sutures are 

 black. The elytra are nearly transparent, the veins showing as 

 lighter lines near the base and darker lines toward the apex, which 

 also is somewhat smoky. The body above is black, the border of 

 the abdomen is yellow beneath, the rest of the body is yellow, except 

 that the central part of the thorax and the basal portion of the 

 abdomen are black. 



The life history was studied in Maine (20, p. 68) some years ago. 

 There seemed to be a fairly distinct migration from grasslands to 

 cats at the time oats were in a succulent period of growth. 



The nymphs are rather easily distinguished by the markings on the 

 head, which are very similar to those of the adult. The color is 

 usually a darker green, the head is more rounded, and the abdomen 

 is slender. The successive instars have not been differentiated- 



As mentioned on page 3 of this circular, this leaf hopper is the 

 carrier of the virus causing the " yellows " of aster and of other 

 plants (ii, p. 65 If). 



The ready migration may lessen the efficiency of rotation and 

 clean culture ; yet it was noticeable that very few were to be found in 



