CHAPTER II. 
CLASSIFICATION OF DIPTERA, WITH AN INTRODUCTORY AC- 
COUNT OF THE ANCIENT AND MODERN CLASSIFICATION OF 
INSECTA. 
THE classification of all animals must necessarily be subject to 
continual change and re-arrangement, as the discovery of new species 
and genera, and the study of known forms, takes place. It is usually 
a matter of no little interest to compare the ancient and modern 
methods of arrangement, and as the Diptera, with the rest of the 
Insecta, have been subject to much alteration in their systematic 
position, we will here consider the old modes, and also in some 
degree follow the rise of Entomology. Several hundreds of years B.c., 
insects had attracted the study of the philosophers, but as all the 
works were burnt in the libraries, we are comparatively in the dark 
upon the subject, prior to the time when the great naturalist, Aristotle, 
wrote. We glean from his writings that much was known before his 
time of the subject of Entomology. Pliny also tells us that Hippo- 
crates, in the 80th Olympiad (5th century B.c.), wrote on insects. 
To Aristotle we are indebted for the first account of the Diptera; he 
divided them into two great sections, making the defensive weapon 
the point of difference. Section I. he called Zmprosthocentra, and 
II. Ofisthocentra; the former, he said, possessed an oral sting, the 
latter an anal. 
A great number of men immediately following Aristotle wrote on 
insects, both in Greece and Rome, amongst whom we may mention 
Democritus, Meander of Heraclea, Virgil, Fabianus, Pliny, and 
M. Varro. 
Pliny classified insects into three groups: 
1. Flying insects, 
2. Naked-winged insects, 
and 3. Protected-winged insects, 
his eleventh book being entirely devoted to insects. Some few 
unimportant writers followed, but until we reach the sixteenth century 
