LETTERS ON ENTOMOLOGY. J 09 
whether winged or not, are in reality flies, have 
trunks and no teeth. Reaumur also places the 
grasshoppers among the flies. There is another 
species, which however is scarce, that of flies 
which have a long pointed head like a bird's 
beak, at the end of which are the instruments 
with which it feeds. A very pretty fly which 
hovers round flowers is an example of it, and has 
its long head split at the end, which opens like 
a beak. 
An instance of the importance of the differ- 
ence in the form of the head, I can give you in 
those flies which sometimes in summer bite so 
sharply even through a covering, and instantly 
draw blood. To a superficial or even attentive 
observer, they exactly resemble the common 
house-flies, which often fall a sacrifice to the 
unfortunate likeness ; yet they are not even of 
the same genus, the culprit being of the genus 
stomoxys, armed with a horny sharp-pointed 
weapon, and the innocent victim of the genus 
musca, having only a soft blunt organ for suction. 
Another important difference is between the 
weapons they carry on the tail. Those which are 
armed with a sting are but too well known ; but 
others are formed in a manner no less admirable 
and more harmless. Many females of the fly 
