NATURAL HISTORY. 139 
fir fight. Thefe claffes which are under the former; are charaéterized 
from the trunk, or from the mouth void of, or furnifhed with teeth, 
and having the head made in the form of atrunk. Thefe are three in 
Number, the firft of which are Flies, with a fhort body, and more 
broad than thick; the fecond is thofe that have a long body, and the 
third is the Flies, whether long or fhort, that have the bodies joined ta 
the corflet by a fingle thread. 
| In order to characterize the kind of Flies which ought, to be placed 
. Under thefe claffes, Reaumur particularly attends to the conftant varie- 
ties which may be taken from the carriage of their wings, the fhape of 
the feelers, the carriage of their trunks, of the other external parts of 
the body, and more efpecially from the hinder parts. Flies of different 
Xinds, may be confidered while they are at reft, or while they are creep. 
Mg, as well as in the different carriage of their wings, which is very evi- 
dent in Butterflies. But there are more Flies that carry their wings pa- 
Tallel to the plane of pofition, than there are that keep them in inclined. 
directions. oe 
Among thofe that carry their wings parallel to this plane, fome hold | 
them like oars. Their direction is perpendicular to the length of the 
body, which is not covered by them at all. Of this kind are many of 
the long water Flies, and of thofe that have two wings, befides fome 
inds of Tipux. Other Flies carry their wings in fuch a manner, 
that they cover one part of the body, and ‘not the other, whether the 
lie has two wings or four, unlefs one of the upper wings fenfibly in- 
trenches upon the other upper wing. Among the Flies with two wings, 
the blue fleth Flies, and the common houfe Flies, are inftances of this kind. 
__The wings of feveral forts of Flies, crofs each other over the body, and 
When this is done more or lefs, there arifes differences eafy to be ob- 
ferved, The wings of feveral Flies that crofs the body, are roundith, 
8nd are not exaétly parallel to the plane of pofition. The wing that is 
© uppermoft, is more elevated over the line on the middle of the bo- 
dy, than on the fides. Thus the wings of thofe are difpofed which pro- 
“eed from the baftard Caterpillars. Some Flies have wings placed on the 
_Dack, oneagainft another, and they are in a plane perpendicular to that of 
the pofition. Several forts of fmall long water-flies, and feveral forts of 
Ucerons, carry their wings in this manner. ‘This is alfo obfervable in 
the Flie called the Ephemera. 
. the wings of feveral other Flies, are applied obliquely againft the 
fides, and they meet over the body, at the inner edge, forming a fort 
faroot. Such is the manner of the fmall Lion Puceron. Other 
lies have their wings likewife applied to the fides, but then they bend 
“own over the back, making almoft a flat roof; as, many of the Flies, 
Which in their firft ftate, were water Moths. Lattly, other Flies keep 
their wings obliquely to the plane of pofition, and in fuch a manner, 
at they meet under their bellies. 
Other varieties in Flies, proceed from the texture of their wings. 
v ey are generally like a fort of fine gauze, for they have every where 
. Nearly equal tincture and tranfparency; however the wings of feveral 
forts of Flies are not very tran{parent, afd others are quite opaque ; 
“fomuch, that at a diftance, they might be taken for the wings of 
Utterflies. Thefe are alfo called by Reawmur Papillionaceous Flies, 
‘at have their wings half tranfparent. Among the Flies with four 
B : wings, 
