106 UTILIZATION OP MINUTE LIFE. 



Fire-flies (Elater], of which I have spoken at 

 length in my work on Phosphorescence, are employed 

 in some countries as lights, as ornaments, and to 

 kill mosquitoes. 



A dipterous insect, belonging to the genus 

 Stomoxys, has been spoken of by the Abbe Moigno, 

 formerly editor of the "Cosmos," a French periodical, 

 as capable of producing truffles, hence it has been 

 termed mouche trufigene, or the truffle-producing fly. 

 But this subject, which was brought forward by M. 

 Ravel, is an illusion : the persons alluded to thinking 

 that the truffle is the product of this fly as the gall-nut 

 is produced by the Cynips I It required the entire 

 weight of M. Dufour's evidence to refute these errors, 

 and to convince those concerned that the truffle is a 

 fungus like the mushroom, springing from seeds, and 

 not the result of an insect's bite upon the oak-roots. 

 That eminent naturalist showed also that several 

 insects lived upon truffles, and were we to attribute 

 the formation and growth of this fungus to an insect, 

 there are some hundreds which we might look to 

 with equal reason. 



I now turn to the common house-fly (Musca do- 

 mestica). Though this insect is not directly useful 

 to us, it contributes, indirectly, to our comforts 

 more than many of us suppose. It is true that Ugo 

 Foscolo used to call flies " one of his three miseries 

 of life," yet the larvae of these insects nourish 



