FLY TIME IN THE FOREST. 151 



large mounds, which are sometimes found every few 

 yards apart all over the wood ; each of which if stirred 

 up with a stick, is found to be a living mass of ants, 

 which emit a strong scent like aromatic vinegar supposed 

 to proceed from certain combinations of formic acid 

 produced by these insects. The ground in such local- 

 ities is in every direction seamed with their runs, along 

 each of which myriads of these little creatures may 

 be seen hurrying to and fro, busily intent upon laying 

 up stores for the coming winter. 



Then as regards winged insect life for we have 

 only space to allude to these matters in the briefest 

 possible way it is equally numerous, and in many 

 forests constitutes, as we have said, a real plague of 

 the first magnitude, rendering certain sections of country 

 quite uninhabitable in "fly time." One must have 

 seen and experienced its torment, in a really bad fly- 

 stricken district, to realize the full extent of this terrible 

 infliction. We allude now to the gnat, mosquito, black, 

 and sand fly tribe, and other winged pests, which 

 attack man. 



These insects, however, must not be regarded as an 

 invariable concomitant of the forest region there are 

 some sections of the forest which are almost free from 

 them and there are places both upon the open tree- 

 less plains, and even in the arctic zone, where they 

 are sometimes found to be almost worse than in the 

 forest itself. 



Alluvial flats and swampy lands, we need hardly 

 say, are as a rule more infested by them than other 

 places; but on the other hand there are certain sorts 

 of flies which are worse on high breezy downs of 

 a dry sandy nature, than in any other locality so 



