THE FARM STREAM 39 
be seen without a 
lens and too num- 
erous even to be 
mentioned here. 
The water is like 
another world of 
life, containing a 
few forms that are 
directly useful to ae me Pe aa insects: @ the ny ees 
otonecta); b, the water-boatman ‘orixa); c, a diving- 
us and many more beetle (Dytiscus); d, a giant water-bug (Benacus). 
that furnish for- 
age for these; containing a few that. are noxious when 
adults, such as black-flies, horse-flies and mosquitoes, anda 
host of other forms, all of interest to the naturalist, but not 
known to be of practical importance. They are all a part 
of the native population of the stream, and each has a share 
in carrying on its natural social functions. 
In the water as on land, green plants represent the great 
producing class, while animals and parasitic plants are the con- 
sumers. And among 
the animals there 
are herbivores and 
carnivores, parasites 
and scavengers. 
One who but casu- 
ally examines the 
animal life of the 
stream is apt to see 
chiefly carnivorous 
forms; for these are 
most in evidence: 
po eee ee 
dobson larva, or hellgrammite, Corydalis cornuta (after where, herbivores, 
Lintner); c,an orl-fly larva, Sialis (after Maude H. : 
Anthony). being poorly 
