GNAT. 
39‘2- 
vigour from the warmer and moister atmosphere 
of the regions of the Western Hemisphere. 
The true structure of the proboscis or piercer of 
the Gnat, which, in its immediate operation, pro- 
duces no very acute pain, but which is so often 
succeeded by such troublesome consequences, is 
not very easily determined. It seems however to 
consist of an external scaly sheath or tube, longi- 
tudinally divided by a continued slit, and so flex- 
ible as to be conveniently doubled or bent in a 
greater or less degree while the secondary or in- 
cluded tube is in the act of absorption. This se- 
condary or included tube appears to consist of five 
parallel, linear parts, forming by their junction 
or juxtaposition a firm, yet exquisitely fine sucker, 
which is forced into the skin of the animal at- 
tacked by the Insect. The swelling which takes 
place after the bite must be supposed to be owing 
to some acrimonious fluid injected into the punc- 
tured part, and which may cause the blood to 
flow with greater facility into the proboscis during 
the time that organ is employed. 
Culcx pidicaris, or Tvlidge, is a much smaller 
species, and is distinguished by having the wings 
marked by three dusky spots. 
Culex reptans is also a very small insect, and is 
of a black colour, with transparent wings, and 
the legs marked by a white bar. It is })articu- 
larly troublesome in marshy districts during the 
evening, by its creeping motion on the skin of the 
face, &c. 
