BULLETIN 195. CALIFORNIA GRAPE ROOT-WORM. 3 



never been investigated. ' ' The first actual observation on the root-feed- 

 ing habits on the grape in this country, so far as we know, was made 

 by Mr. 0. Butler of this station, who found it on the roots of vines near 

 Lodi in 1905. 



Its Name. A beetle was described in 1602 by Aldrovandi, 1 which 

 seems to answer the description of this species ; but it was placed in 

 the wrong group by this author, and it was also before the adoption 

 of the binomial system of nomenclature. It has been described under 

 two or three different generic names since, but the one now adopted is 

 Adoxus, given by Kirby in 1837. 



Linnaeus in 1741 described a beetle, to which he gave the specific 

 name obscunts. This is now known as Adoxus obscurus, and is the 

 name that has been applied to the black form of the beetle occurring 

 in California and elsewhere in the United States. Mayet 2 states that 

 obscurus Linn, is somewhat larger than vitis, entirely black, and found 

 on a plant (Epilobium) of the marshy prairies, sometimes upon "trifli" 

 clover, but never on the vine. Dr. Horn 3 states that the only known 

 species of the genus inhabits- Europe and the northern part of our own 

 continent, and that it varies in a similar manner in both regions. 



In California it is certain that both the black and brown forms are 

 the same species. Wherever the beetle was seen during the past two 

 years the two forms occurred in about equal numbers, and were found 

 interbreeding in all combinations. A large number of specimens of A. 

 vitis were kindly sent to us by Professor Valery Mayet of Montpellier, 

 France, and they appeared to be identical with the brown form occur- 

 ring here. He also sent us two specimens of A. obscurus, saying that 

 these were very rare and never found on the vine, as noted above. They 

 were slightly larger than the black form occurring on the vine here. 



On account of the great difference in food plants it would appear 

 that the obscunts of France is a distinct species from that of vitis; but 

 an inquiry into the geographical distribution of the two forms seems to 

 indicate that it is simply a case of a dichromatic species, with one or the 

 other of the two forms predominating in the different regions, with the 

 exception of the California vineyards, where both forms occur in about 

 equal numbers. 



On account of priority the correct specific name should be obscurus 

 Linn, representing the black form, while vitis F. should be applied to the 

 bi colored variety. 



In France this insect goes by the common name of Le Gribouri or 

 Ecrivain, the scrawler or writer; but since these names are hardly 



1 Des Insectes, 1G02. 



2 Insectes de la Vigne, p. 322, 1890. 

 3 Amer. Entomol. Soc., vol. 19, p. 196. 



