BULLETIN 195. CALIFORNIA GRAPE ROOT- WORM. 5 



at least as far south as Tulare County, California. This region, includ- 

 ing also the Eastern States, with the exception of the Sierras in Cali- 

 fornia, is occupied by the bicolored variety vitis F. The melanotic form 

 or true obscurus L. has been found besides in California, in Colorado, 

 and one specimen, among many thousands of the variety vitis F., at Port 

 Angeles, Washington. 



' ' The insect is found throughout Siberia, where in the Amoor region 

 and around Lake Baikal, the true obscurus L. according to the cata- 

 logue of L. Von Hey den, which clearly differentiates the two forms 

 is the dominant one, and perhaps as much a race there as it is here. 

 In west Siberia the variety vitis F. seems to be the predominant one. 

 This peculiarity of distribution is in keeping with that of many of the 

 other species of beetles that are common to both continents, the eastern 

 specimens related to the more western of those of the old world, while 

 ours are more closely related to those of the highlands of southeastern 

 Siberia, etc., the so-called Japano-Manchurian region." 



It appears then that the obscurus form living upon its native food 

 plant in the Sierra Nevada mountains has transferred itself to the vine- 

 yards, but here instead of obscurus occurring exclusively, both obscurus 

 and vitis occur in about equal numbers. The points at which the beetles 

 were reported as injurious this year from Merced to Marysville, parallel 

 with the Sierras, points strongly to the fact that it has come down from 

 the mountains and established itself in the vineyards of the valley. 

 The beetles also occur in the Sonoma Valley, and this may be accounted 

 for by the fact that its native food plant is also found here. According 

 to Jepson, 1 the fire weed (Epilobium spicatum) has been collected in 

 western and middle California only in Sonoma County, near Guerne- 

 ville. The distribution of this insect, with its varying color forms in the 

 different regions and its apparent transfer to cultivated plants, present 

 an interesting biological problem. 



As an economic species it is widely distributed in Europe, occurring 

 particularly in the vineyard sections of France, Italy, and Algeria. 

 Here in the United States it seems to have gained its strongest foothold 

 in California. According to Cooke it was reported from six of the 

 principal grape sections of the State as far back as 1882. Within the 

 last two or three years it has been most abundant in the Sacramento and 

 San Joaquin valleys, and in the coast region near Sebastopol and 

 Healdsburg. 



Related Species. In the Eastern States, particularly in the grape 

 growing sections of Ohio and the Chautauqua belt of New York, there 

 is a similar insect called the grape root- worm (Fidia viticida Walsh) 

 that does very serious injury to the vineyards. This insect has been 



1 Flora of Western and Middle California, p. 329. 



