224 JRedt's Experiments on the Generation of Insects, 



curing all the outlets in the box, they were unable to effect 

 this. Gradually they became more quiet, and, after some 

 time, lay motionless, as if asleep. Shrinking into themselves, 

 they imperceptibly took the form of an egg, and, by the 

 twentieth day, they had all assumed this figure. At first they 

 were of a white colour, but by slow degrees became first 

 golden, then red. Some remained of this colour, but the rest 

 continued to become darker and darker, till they were quite 

 black ; and, from soft and tender, their skin had changed to 

 the hard and brittle shell of the chrysalis or aurelia. On 

 examining these more closely, he found the black ones were 

 more strongly marked than the others, which were nearly 

 smooth. At the end of eight days the red chrysalides burst, 

 and from each issued a fly of a dull ash colour, " turbid, dis- 

 mayed, and, so to speak, wrinkled and unfinished," with its 

 wings yet unfolded ; but, in the space of a quarter of an hour, 

 it dilated its little body, unfolded its wings, " and, relinquish- 

 ing the sad ash colour, it was dressed in a vivid green, mar- 

 vellously brilliant. It was now so much larger than before, 

 that it seemed impossible to conceive that its little shell could 

 have contained it." In fourteen days some of the black ones 

 burst, and produced a larger fly, " black, marked with white, 

 hairy on the abdomen, and red at the nether end ; such as 

 daily frequent butchers' shops, or any place where there is 

 dead flesh. At first they were like the others, slow, slovenly, 

 and sluggish in their appearance." In seven days after, the 

 rest of the chrysalides burst, and liberated certain little black 

 flies, smaller and brisker than both the other kinds, which 

 Redi says he believes to have been undescribed by any former 

 naturalists. It would be a useless task to pretend to ascertain 

 the exact flies Redi speaks of, as, notwithstanding his vivid 

 descriptions of their beauty, his terms are too general to afford 

 any assistance in the enquiry. Our main point is to state how 

 he attained his grand object, without entering into minute and 

 unnecessary details. 



So many different flies from the same kind of flesh, did not 

 dismay, but, on the contrary, stimulated him to fresh exer- 

 tions ; instead, therefore, of only one kind, he put many into 

 different boxes, and obtained the same result as before, except 

 that the different species of insects were more numerous. He 

 next put some skinned river frogs into a glass vessel, which 

 he left open ; on the following day, he found them covered 

 with worms, some sporting in the fetid liquor that had stilled 

 from the carcass, while the rest depastured on the frogs. On 

 the third day he found they had all decamped, leaving nought 

 of the frogs but the bones. Some fish from the Arno were the 



