502 MODERN CLASSIFICATION OF INSECTS. 
undergoing the change to the pupa in the abdomen of the mother ; 
and being deposited in the shape of a large oval mass covered by 
a thick skin. 
The situation of the Diptera amongst the orders of insects is consi- 
dered by Mr. MacLeay to be intermediate between the Lepidoptera, 
with which they are supposed to be connected by means of such in- 
sects as Pterophorus abr. (Phalénes tipules D. G.) and Psychoda 
Latr. (Tinearia Schill.*) and the order containing the fleas, Apha- 
niptera ; which latter relationship is deemed to be effected by means 
of Hippoboscat , Nycteribia, and Pulex ; whilst the analogous appear- 
ance exhibited by different species in almost every Dipterous family 
with the Hymenoptera, has not failed to attract the attention of every 
observer. These orders are accordingly analogically opposed to each 
other in the mandibulated and haustellated columns of the systems of 
Savigny, MacLeay, and Kirby and Spence. (See K. and S., vol. iv. 
p: 412—415.) 
It is to Aristotle that we are indebted for the first indication, as well 
as the name, of this order; and by whom it was divided into two 
sections, one of which (Emprosthocentra) he distinguished from its 
counterpart amongst the Tetraptera (Opisthocentra) from possessing 
an oral instead of an abdominal sting. Swammerdam, pursuing the 
principle of metamorphosis, united one portion with the Coleoptera, 
Hymenoptera, &c. undergoing an incomplete metamorphosis, whilst 
the remainder, undergoing a coarctate metamorphosis, he erroneously 
placed with the Ichneumones minuti Zinn. Linnzeus, in his later 
works, established it in its present extent, in which respect he was 
followed by De Geer. Fabricius, however, pursuing the cibarian cha- 
racters, united it with the Anoplura Leach, Trachean Arachnida La¢r., 
&c. under the name of Antliata, a step which has not been adopted 
except by his immediate followers. Clairville also proposed for it the 
name of Halteriptera. More recently Dr. Leach proposed to establish 
the Linnean genus Hippobosca as a distinct order, under the name 
of Homaloptera. 
* Burmeister thinks the long rostrated Bombyliide and Tabanide, which he 
places in conjunction, lead to the Lepidoptera (De Insect. Syst. Natur. p. 25.). 
This relationship is, however, more apparent than real; the labium of the Diptera 
being lengthened at the expense of the maxilla, &c. ; whereas, in the Lepidoptera, 
the maxillz are developed at the expence of the labium, &c. 
+ The stirps Pupipara (Hippobosea), &c. is also deemed by Mr. MacLeay as 
establishing the passage between the classes of Haustellata and Arachnida. I have 
introduced some observations upon this transition in my remarks upon this stirps. 
