8 EN TOMOLOGY 
to a hypothetical form like the trochosphere larva of recent 
polycheete annelids. 
Orders of Insects.—Linnzus arranged insects in seven 
orders, namely, Coleoptera, Hemiptera, Lepidoptera, Neurop- 
EIG20! Fic. Io. 
Campodea. Length, Lepisma. Length, 
3 mm. ro mm. 
tera, Hymenoptera, Diptera and Aptera. The wingless in- 
sects termed Aptera were soon found to belong to diverse 
orders and the name has now become so ambiguous as to meet 
with little approbation. 
From the Linnzean group Hemiptera, the Orthoptera were 
set apart; the old order Neuroptera, a heterogeneous and 
unnatural group, has been split into several distinct orders, 
and many other changes in the classification have been neces- 
sary. 
Without entering any further into the history of the sub- 
ject, it 1s sufficient to say that increasing discrimination on the 
