CLASSIFICATION Za 
for boring, sawing or cutting. Larve with complex mouth 
parts and frequently abdominal legs. Phytophagous. Ex- 
ample, Tremex (Fig. 31). 
Cat and dog flea, Ctenocephalus canis. A, larva (after KUNCKEL D’HERCULAIS); 
B, adult. Length of adult, 2 mm. 
Suborder Aculeata (Heterophaga, Petiolata).—Abdomen 
petiolate or subpetiolate; first abdominal segment transferred 
to the thorax. Ovipositor 
often modified to form a 
sting. Larvze apodcus. Ex- 
ample, Apis (Fig. 277 )- 
Interrelations of the 
Orders.—The modern clas- 
sification aims to express 
relationships, and these are 
most clearly to be ascer- 
tained by a comparative 
study of the facts of anat- 
omy and development. 
The most generalized, Or Tremex columba. A, imago; B, larva 
(with parasitic larva of Thalessa attached). 
primitive, insects are the Natural size.—After RILEy. 
Thysanura. Subtracting 
their special, or adaptive, peculiarities, their remaining charac- 
ters may properly be regarded as inheritances from some 
vanished ancestral type of arthropod. This primordial type, 
