CLASS V. IJJSECTA. 
289 
Nation. He observed that the mouth contains the whole of the 
usual parts which, under various modifications, exist in all insects : 
the mandibles are perfectly distinct from and unconnected with the 
maxillae : the maxilla! arc inserted behind, and somewhat below the 
'Uandibles, whose base they conceal ; and the articulation of the 
lahrum is very evident from its semitransparency.” Leach. , Zool. 
Misc. vol. iii. 
Mr. Kirby, in the second volume of his Monographia Apum An- 
glia, gives the following account of Slylops Melitta: “ Upon this in- 
sect {Melitta nigro-tenea ) L discovered, last spring, a very singular 
animal, which seems appropriated to the present genus. I had pre- 
viously more than once observed upon other species something that 
I took to be a kind of Acants, which appeared to be immovably fixed 
just at the inosculations of the dorsal segments of the abdomen, at 
length, finding three or four upon a specimen of Melitta nigro-tenea, 
- I determined not to lose that opportunity of taking one off to ex- 
amine and describe ; but what was my astonishment when, upon 
niy attempting to disengage it with a pin, I drew forth from the 
body of the Melitta a white fleshy larva, a quarter of an inch in 
length, the head of which I had mistaken for an Acarus ! After I 
had examined one specimen, 1 attempted to extract a second ; and 
the reader may imagine how greatly my astonishment was increased, 
when, after I had drawn it out but a little way, I saw its skin burst, 
and a head as black as ink, with large staring eyes and antennae, 
consisting of two branches, break forth, and move itself briskly 
from side to side. It looked like a little imp of darkness just emerg- 
ing from the infernal regions. My eagerness to set free from its 
confinement this extraordinary animal may be easily conjectured. 
Indeed I was impatient to become better acquainted with so singular 
a creature. When it was completely disengaged, and I had secured 
it from making its escape, I set myself to examine it as accurately 
as possible ; and I found, after a careful inquiry, that I had not only 
got a non-descript, but also an insect of a new genus, whose very - 
class seemed dubious.” For further information on this Order I 
must refer the reader to the eleventh volume of the Transactions of 
the Linnean Society, Sowerby's British Miscellany, and Leach's Zoolo- 
gical Miscellany, vol. iii., all of which contain figures of the insects 
«f this Order. 
Order XV. DIPTERA. Lime, Leach, Latr., <§-c. 
Class Antliata. Fabr. 
The insects composing this Order are distinguished from all other 
‘nsects by the following characters. Wings two, naked, unprotected 
tiulteres (poisers or balancers) placed behind, and generally beneath 
T 
