254 ENTOMOLOGY 
upon 78 species of plants, in captivity upon 458 species (30 
under stress of hunger, the rest freely), and refused only 19 
species, most of which (such as larkspur and red pepper) 
had poisonous or pungent juices, or were otherwise unsuit- 
able as food. ‘The migratory 
Fic. 247. 
locust is notoriously omniv- 
orous, and perhaps eats even 
more kinds of plants than the 
eypsy moth. 
Galls.—Most of the conspic- 
uous plant outgrowths known 
as “galls”? are made by in- 
sects, though many of the 
smaller plant galls are made 
by mites (Acarina) and a few 
plant excrescences are due to 
nematode worms and to fungi. 
Among insects,Cynipidee ( Hy- 
Holcaspis globulus. A, galls on oak, menoptera ) are pre-eminent 
natural size; B, the gall-maker, twice as oall-makers and next to 
natural length. 2S aaa Bd oe ee - 
. these, Cecidomyiidee ( Diptera), 
Aphididz and Psyllide (Hemiptera) ; a few gall-insects occur 
Fic. 248. 
Galls of Holcaspis duricoria, on oak. Natural size. 
among Tenthredinidee (Hymenoptera) and Trypetide (Dip- 
tera), and one or two among Coleoptera and Lepidoptera. 
Cynipide affect the oaks (Figs. 247, 248) far more often 
