NOTES ON THE CUCUMBER BEETLES. 75 
articles was published on this species from 1901 to 1902 by Mr. E. J. 
Wickson. a There are also in the Bureau unpublished accounts of 
injury to orange trees, the leaves of which are skeletonized. 
Two natural enemies of this species have been observed; one, the 
tachina fly, Celatoria diabroticx Shim., also described as Celatoria 
crawii by Mr. Coquillett in 1890. b The other is a spider, also observed 
by Mr. Coquillett, and known as Xysticus gulosus Keys. c 
THE WESTERN STRIPED CUCUMBER BEETLE. 
(Didbrotica trivittata Mann.) 
The western striped cucumber beetle (Diabrotica trivittata Mann.), 
which is very closely related to the eastern striped cucumber beetle 
(Diabrotica vittata Fab.), is common throughout the State of Cali- 
fornia and extends into Oregon, where it practically replaces the 
eastern form, although, according to records, it is not nearly so 
injurious. We have indeed few records of injurious occurrences. 
Since 1898, however, when the writer recorded injuries by this species 
to cucurbits, there have been scattered reports of injuries to this 
class of plants, all of which it attacks. It attracts much more atten- 
tion when it occurs on fruit trees, and has been accused of considerable 
injury to ripening peaches and apricots. Like the eastern form, also, it 
is found associated with a closely related species, in this case the western 
twelve-spotted cucumber beetle just considered. From the .striped 
cucumber beetle of the East it may be separated chiefly by its darker 
colors. The antennas are entirely piceous, the thorax bears two 
coalescing foveas, and the legs, with the exception of the bases of the 
femora, are entirely black. 
In 1903 we received report of injury by this species to various 
plants in the neighborhood of Dehesa, Cal., and in July, 1905, to beans, 
cucumber, squash, and the silk of corn in the vicinity of Salem, Oreg. 
In this latter locality it was associated with the common Diabrotica 
soror Lee. August 11, 1907, Prof. E. S. G. Titus stated that melons 
had been seriously injured for two years past in the vicinity of 
Imperial Junction, Cal. During that year and in succeeding years 
this species was found, by various agents, collaborators, and special 
correspondents who visited the sugar-beet region of the Pacific States, 
in sugar-beet fields, where, however, it was doing no serious injury. 
« Pacific Rural Press, June 30, 1900, et seq. 
& Coquillett: Insect Life, Vol. II, p. 233, 1890. 
cLoc. cit., p. 74, 1890. 
