INSECT PURIFIERS AND INSECT- FARE. 169 



precautions of man, unless these were aided by scavenger 

 Insects, those myriads of Flies and carrion Beetles, whose per- 

 petual labours even in our tempered climate, but infinitely more 

 so in warmer regions, are essentially important to cleanliness 

 and health. 



A use of this nature, and one performed perhaps to an 

 extent we little think of, is the purification of standing waters 

 by the innumerable Insects which usually inhabit them. We 

 have witnessed ample proof of the efficacy, in this respect, of 

 Gnat Larvae, when keeping them to observe their transfor- 

 mations. Water, swarming with these " Lives of Buoyancy," 

 has been perfectly sweet at the end of ten days, while that 

 from the same pond, containing only vegetable matter, has 

 become speedily offensive. 



As commissioned agents, ministering more or less directly to 

 our various pleasures, we owe no slender obligation to Insects. 

 Besides imparting variety and animation to summer scenes 

 by their "ceaseless hum" and endless diversity of form, they 

 assist in the support of most of our favourite songsters of the 

 garden and the grove. The red-breast, the wren, and the tit- 

 mouse live almost wholly upon worms and Insects, which also 

 serve the black-bird and the thrush as meat before a fruit 

 desert. To the delicacies of our tables they are also indirect 

 contributors. Our game grows plump on the nurselings of 

 the Ant-hill, the larvse and pupae improperly called eggs. 

 Our fish fatten on " the Fly " in all its varieties ; and even 



