June, ’24] 
severin: beet leafhopper enemies 
375 
for a long time on the American continents. It is reported as almost continuous in 
its distribution, but it cannot now be verified for the tropics. C. ambrosioides is a 
native in warm temperate and tropical America and is now common from eastern 
Canada and California to Brazil and Argentine. It occurs only as an introduced 
species in the northern part of its range and perhaps in the extreme south in South 
America. 
The present known distribution of the beet leafhopper corresponds 
with the geographical range of Red Stem Filaree (Erodium cicutarium ), 
the most important winter host plant in which the dark overwintering 
adults deposit their eggs and on which the spring brood develops in 
California. According to Thornber (9) Red Stem Filaree now covers 
parts in Washington, Idaho, and Texas and the whole of Oregon, Cali¬ 
fornia, Nevada, Arizona, New Mexico and Utah. Hemsley (6) records 
Red Stem Filaree from “North Mexico, Monterey (Eaton and Edwards); 
South Mexico, Tacubaya (Bourgeau, 30), at the foot of the mountains of 
Orizaba (Schiede and Deppe), without localities (Hahn, Bates, etc.) 
Hb. Kew.” Specimens of E. cicutarium are in the herbarium of the 
botanical department at the University of California collected by Dr. 
Nicolas Illin labeled as follows: “Flora Argentina, Terriorio del Chubut, 
1903, No. 24.” 
Red Stem Filaree is supposed to have been originally introduced into 
America from the Mediterranean basin by the Spaniards although there 
is some difference of opinion among botanists. According to Brewer 
and Watson (3) E. cicutarium is “very common throughout the State, 
extending to British Columbia, New Mexico, and Mexico; also widely 
distributed in South America and the Eastern Continent. It has been 
generally considered an introduced species, but it is more decidedly 
and widely at home throughout the interior than any other introduced 
plant, and according to much testimony it was as common throughout 
California early in the present century as now. ’ ’ The possibility that the 
beet leafhopper was accidentally introduced in Red Stem Filaree from 
Europe is entirely out of consideration for if this plant was introduced 
into America from the Mediterranean basin it w r as through the seed 
carried in the wool of sheep. 
A study should be undertaken as to the geographical distribution of 
the beet leafhopper for it does not seem possible that the range of this 
insect occurs from Washington and Idaho, south through the tropics into 
Argentine, South America. Dr. E. C. Van Dyke, an authority on the 
distribution of the Coleoptera, informed the writer that species of beetles 
are widely separated in the north and south temperate regions and that 
