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THE STUDY OF INSECTS . 
CC. Head not prolonged into a trunk. 
D. Louse-like insects of small size ; body less than one-sixth 
inch in length. 
E. Antennae with not more than five segments. (Bird-lice.) 
p. ioo. Mallophaga. 
EE. Antennae with many segments. (Book-lice.) p. 98. 
CORRODENTIA. 
DD. Insects of various forms, but not louse-like, and, except 
in the case of some ants, with the body more than one-sixth 
inch in length. 
E. Abdomen with short, conical, compressed, many-jointed 
caudal appendages. ( Cockroaches .) p. 104...ORTHOPTERA. 
EE. Abdomen without jointed caudal appendages. 
F. Legs fitted for jumping. {Wingless Locusts, Grasshop¬ 
pers, and Crickets.) p. 104.ORTHOPTERA. 
FF. Legs fitted for running, 
G. Abdomen broadly joined to thorax. 
H. Body linear. {Walking-sticks.) p. 104. 
ORTHOPTERA. 
HH. Body white and somewhat ant-like in form. 
(Termes .) p. 95.ISOPTERA. 
HHH. Body neither linear nor ant-like in form. 
( Wingless Fire fly et al.) p. 494. COLEOPTERA. 
GG. Base of abdomen strongly constricted. {Ants et al.) 
p. 599 .*. Hymenoptera. 
BBB. Mouth-parts formed for sucking. 
C. Small abnormal insects in which the body is either scale-like 
or gall-like in form, or grub-like and clothed with wax. The 
waxy covering may be in the form of powder, of large tufts or 
plates, of a continuous layer, or of a thin scale, beneath which 
the insect lives. {Coccidee.) p. 121 .Hemiptera. 
CC. Body more or less covered with minute scales, or with 
thick long hairs. Prothorax not free {i.e., closely united with 
the mesothorax). Mouth-parts usually consisting of a long 
“tongue” rolled beneath the head. p. 191. Lepidoptera. 
CCC. Body naked, or with isolated or bristle like hairs. 
D. Prothorax not well developed, inconspicuous or invisible 
from above. Tarsi five-jointed. Mouth-parts developed 
into an unjointed trunk; palpi present, p. 413.... Diptera. 
DD. Prothorax well developed. 
E. Body strongly compressed ; tarsi five-jointed. {Fleas.) 
p. 49°. Siphonaptera. 
