14 BULLETIN 254, 17. S. DEPARTMENT OF AGRICULTURE. 
around Columbia, Mo., "hi such numbers that they could be gath- 
ered up by the bushel." x Strong winds in midsummer no doubt are 
responsible in many cases for what may seem a natural migration. 
ENEMIES. 
PARASITES. 
Probably the most effective enemies of the sharp-headed grain leaf- 
hopper are its egg parasites, two species of which were reared in great 
numbers during the summer of 191-4, while the writer was stationed 
at Tempe, Ariz. Both of these egg parasites were new to science, and 
Mr. J. C. Crawford 2 has described one as Gonatocerus gibsoni; the 
other Mr. A. A. Girault will describe as Abbella auriscutellum. Had 
it not been for these two egg parasites considerable damage would 
probably have been done by the jassid during the summer months. 
One of these parasites, Gonatocerus gibsoni, not only held the species 
in check but practically eradicated the pest in the Salt River Valley 
of Arizona. In this valley there was from 75 to 95 per cent of 
parasitism among the eggs of the second generation of the grain jassid 
between May 15 and June 15. Mr. J. H. Newton, a temporary 
assistant in the Bureau of Entomology at Tempe, found an 85 per cent 
parasitism from several hundred egg pockets examined. 
Mr. George G. Ainslie, while in Florida during the spring of 1914, 
reared two species of egg parasites; one of these, reared in consider- 
able numbers, has been determined by Mr. Gahan as Bracliistella 
acuminata Ashm. Mr. Ainslie recorded a 79 per cent parasitism 
among eggs examined. Mr. R. A. Vickery reports having reared many 
parasites of Ufens niger Ashm., as determined by Girault. Five or six 
were reared from each egg. 
There are many parasites which affect the Jassidse and it is quite 
likely that this species comes in for its share. Although none has 
been recorded as having been reared from the gram leafhopper, yet 
in all probability some of the members of the families Proctotrypidse 
and Dryinidse materially help in suppressing its numbers. Several 
adults of Athysanus exitiosus Uhl. were taken which were parasitized 
by one of the Proctotrypidse which appeared in the form of an external 
sacklike structure within which the parasite sucked the juices from 
the abdomen of the host. These adults of A. exitiosus were swept 
from fields where the grain jassid was very numerous. In the report 
of the Hawaiian entomologist and in the papers of Perkins and 
others may be found accounts of various parasites of the Jassidse. . 
The dipterous genus Pipunculus contains parasites of leafhoppers 
and according to Giard they are parasitic especially upon the family 
Jassidse. The order Strepsiptera (the twisted-wing insects) contains 
iOp. cit., p. 20. 
- Crawford, J. C Descriptions of new nymenoptera, No. 9. In Proc. TJ. S. Nat. Mus., v. 48, pp. 577- 
586, Sep.. no. 20S7, May 3, 1915. Gonatocerus gibsoni, new species, p. 586. 
