24 
THE RELATION <>F SPABBOWS TO AGRICULTURE. 
rows prey od cankerworms and other members of the family Geome- 
bridffi. They also have a decided taste for cutworms, army worms, 
and their allies, in destroying which the song, field, chipping, grass- 
hopper, and lark sparrows, and the dickcissel are especially effective. 
But adult sparrows can not be depended upon to check invasions 
of certain insecl pests, especially hairy caterpillars, because they do 
not eat them. With orchard 
trees and others festooned 
with the webs of the fall web- 
worm, I have seen the spar- 
rows, although they were 
abundant in the vicinity, re- 
fuse these insects and select 
others. At Marshall Hall, 
Md., on the level bluff across 
the Potomac from Mount Ver- 
non, is a fertile farm, on which 
the field habits of sparrows 
have been carefully studied 
(see pp. 29-45). On this 
farm during August, 1898, 
the tobacco worms practically 
ruined the tobacco crop. I 
collected there at that time 
50 sparrows, representing the 
chipping, song, field, grass- 
hopper, Henslow's, and Eng- 
lish sparrows, but subsequent 
stomach examination showed 
that only one of these birds 
had eaten a tobacco worm. 
Weevils, especially such as 
injure clover and strawber- 
ries, they destroy in large 
numbers, which is surprising, 
considering that these insects 
are hard-shelled and protec- 
tively colored. Th ey eat some 
species of leaf -beetles (Chryso- 
melida*) also, but refuse others. Thus they avoid the potato beetle 
(Doryphora tO-linecUa), the two L2-spotted cucumber beetles (Diabro- 
tica 12-punciata and D. vittata), and the bean flea-beetle (Ceratoma 
trifureafa) 9 bu\ consume some Of the less important pests of the bean. 
The .song, field, and chipping sparrows eat the locust leaf-mining 
beetle (Odoniotc dorsalis) and two species of striped flea-beetles 
(SysU na bUmda and S. ekmgata). 
Fi<; 13.— Four common weeds the seeds of which arc 
eftten by sparrows: <i, amaranth; />, crab-grass: c, 
raffwei'd: »/, pigeon-grass. 
