Civic Codperation 131 
site of beneficial. It is only due to the protective color 
scheme of the caterpillars that some escape from the fate 
of becoming food for the parasite brood. 
Besides these parasitic insects, there are others which 
eat the depredators directly. ‘The interesting Mantis, Rear- 
horse or Walking-stick, is one of these; ants and spiders are 
others, which, however, even more than the birds, do not 
make much distinction between friend and foe. The 
larve of the tiger-beetles (Cicindelide) and ‘“ ground-beetles” 
(Carabidz), on the other hand, with some other beetle larvae, 
are more useful caterpillar hunters, because feeding on 
specific injurious insects. Among the most important are 
the “lady-bugs” (Coccinella), whose small-headed, long- 
legged larvee, often prettily colored, prey especially on plant- 
lice and scale-insects. Quite a number of other friends 
could be mentioned. 
While it is well to know these friends, it is in most cases 
impossible to rely on them for much practical help, espe- 
cially in street trees, where wholesale methods of warfare 
become necessary, and no fine distinctions can be drawn, 
i.€., where poison is used, which generally kills both friend 
and foe. 
Civic Cooperation. In the city, unbalanced conditions 
have been created by man and have been maintained so 
long that insect pests have the best chance for growing con- 
tinuously worse, unless special effort is made to keep them 
in check. ‘Theoretically, it would be possible by a supreme 
effort to get rid of all these pests, and then by moderate 
attention to keep them subdued. Practically, the condi- 
tions for securing this result are rarely attainable; especially 
when private owners do not fall in line with the efforts at 
extermination. While much may be done by private asso- 
ciated effort, there are always some persons antagonistic or 
