42 



HISTORY OF FARM 



eqtiipped for fighting, cannot afford to 

 be conspicuous. But if one -will reflect 

 that carnivores raay not maintain 

 themselves indefinitely by eating one 

 another, and will look a little more 

 closely, he will find plenty of the 

 herbivorous forms. These are they 

 whose economic fimction is that of 

 "turning grass into flesh, in order that 

 carnivorous Goths and Vandals may 

 subsist also, and in their turn .pro- 

 claim 'All flesh is grass' " (Coues). 

 The most widespread, abundant, 

 Fig. 23. Immature stages and important of the herbivores of the 



of four common neuropterous ^ 



insects: a. a dragon-fly (A BflAr stream are apt to be the scuds (Fig. 



junttts); b, a damsel-fly ^ \ o 



(Amphiagrion amphipn); ca. 30), the mayfly uymphs (Fig. 22,d) and 



stone-fly {Acroneuna spf); " Jjjf^ao/ 



andd, a may fly {CaUibaetis ^^^q larVffi of midgeS (Fig. 24^). 



Study 4. The Farm Stream 



This study asstmies that there is accessible some creek, or 

 large brook or small river, having rapids and shoals and pools 

 and reed-grown bays in it, all easy of access. If the banks 

 where the work is to be done are too soft, rubber boots for 

 wading, or temporary walks that will make wading unneces- 

 sary, will have to be provided. Each student should be pro- 

 vided with a dip-net for catching specimens, a shallow dish in 

 which to examine them, a lifter with which to transfer them, 

 and a few vials in which small specimens may be examined 

 with a lens. 



A normal condition of the stream is necessary; high water 

 and great turbidity will render the work tmsatisfactory. 



Program — Go over the area marked for examination, begin- 

 ning with the pools having mud bottom, and proceeding to 



