114 TITE OYIPOSITOr.. 



and they have the power of unsheathing It at 

 pleasure. They are armed with what* Mr. 

 Kirby called a long retractile tube, or vagina, 

 which unsheaths an aculeus, or pointed instru- 

 ment like a sting, as fine as a hair. This is 

 introduced into the floret, and by it the eggs 

 are deposited upon the interior valuvle of the 

 corolla just above the stigmata. The accurate 

 entomologist, to whom we owe these observa- 

 tions, has discovered them several times caught 

 prisoners by being unable to withdraw this 

 instrument. He also witnessed the operation 

 of depositing the eggs, after many attempts in 

 which he failed. One day he gathered an ear 

 upon which the flies were actively engaged, and 

 was enabled by the aid of a pocket microscope 

 to view this remarkable process. " I could," 

 he says, " very distinctly perceive the eggs 

 passing one after another, like minute air-bub- 

 bles, through the vagina, the aculeus being 

 wholly inserted into the floret." He adds, " I 

 examined this process for full ten minutes be- 

 fore the patient little animal disengaged itself, 

 and at last it was through my violence that she 

 discontinued her employment, and flew away." 

 If all the eggs that are thus layed in favourable 

 seasons were to be hatched, or if Providence 



