202 INSECT MISCELLANIES. 



The considerable difference of form must prevent 

 the most indifferent observer from confounding 

 gnats with the gad-flies {Tahanidce). Their instru- 

 ment of annoyance is also very different from that of 

 the gnat, being much larger, more formidable, and 

 not less skilfully adapted to its office. The figures 

 will exhibit the difference at a glance. 



Reaumur took advantage of his carriage being 

 stopped in a narrow pass by some oxen, which were 

 surrounded by gad-flies, to study the operation of 

 one which alighted on his hand, by means of a mag- 

 nifying-glass of considerable power. It gave him 

 considerable pain, pierced a deep hole in his skin 

 larger than the prick of a pin, and he afterwards 

 found in the body of the insect seven or eight large 

 drops of blood *. Lambert, in speaking of some fly 

 of this order, says, " they are so very small as to 

 be hardly perceptible in their attacks ; and your 

 forehead will be streaming with blood before you 

 are sensible of being amongst them." Again he 

 says, " I have sat down to write, and have been 

 obliged to throw away my pen in consequence of 

 their irritating bite, which has obliged me every mo- 

 ment to raise my hand to my eyes, nose, mouth, 

 and ears, in constant succession f." It is very 

 probable that our author here means a fly of a dif- 

 ferent family {Stomoxydce, Meigen) from the pre- 

 ceding. One of these is so like the common house- 

 fly (Musca domestica), as to be readily mistaken for 

 it, though the house-fly has no organs fitted for 

 penetrating the skin. Kirby says, " this little pest 

 {Stomoxys calcitrans, Fabr.), I speak feelingly, 

 incessantly interrupts our studies and comfort in 

 showery weather, making us even stamp like the 

 cattle by its attacks on our legs ; and if we drive it 

 away ever so often, it will return again and again to 



* Mem. iv. 230. f Trav. through Canada, i. 126, 127. 



