INTEODUCTION. 9 



Schrank,^ in 1781, recorded the following nine 

 species, viz. Podiira alba, mricUs, nivalis, arhorea, 

 jjhimbea, villosa, aquatica, fimetaria, and monura. He 

 places them all under the genus Podura, and his 

 descriptions of the first eight are word for word the 

 same as those of Linngeus. 



P. monura is described as occurring with and much 

 resembling 0. fimetaria. It is, however, rarer, greyer, 

 and slightly smaller ; the antennae are four -jointed, the 

 eyes black ; the insect is covered with hairs, those on 

 the body being the longest. The chief peculiarity, how- 

 ever, lies in the tail, which is three-jointed, but not 

 double. Moreover, the third segment is described as 

 retractile within the second. The animal jumps, but 

 not very actively. Subsequent writers do not appear 

 to have met with any species answering to this de- 

 scription. I am disposed to think that Schrank must 

 have had before him a specimen with an accidentally 

 mutilated tail. 



De Geer, in the seventh vol. of the edition of his great 

 work published in 1782," treats of Lejnsma and Podura 

 between the flea and the white ant. Of Lepisma, or, as 

 he calls the genus, Forhicina, he mentions only one 

 species, the common L. saccharina. 



Podura he divides, like Geoffi'oy, into two families, 

 one containing Podura and the other long species, the 

 second corresponding to the Smynthuridce. Of the 

 Poduridce he describes P. arborea, nivalis, aquatica, 

 aquatica grisea, ^j/?tm&e«, and ambulans. Of the 

 Smynthuridce he only knew the 8. ater, which, how- 

 ever, he describes with his usual accuracy. Of 

 these the P. aquatica grisea is the only one not in 

 the ' Systema Naturge.' As already mentioned, 

 however, his P. ambulans is not the P. ambulans of 

 Linngeus. 



De Geer's figures enable us to determine several of 

 Linnseus's species which it would be otherwise impos- 



' ' Enumeratio insectorum Austrise indigenonim.' 

 " ' Geschichte der Insecten,' vol. \n, p. 8. 



