14 



INTEODUCTION. 



published a short notice on the abdominal appendages 

 of Machilis ijolypoda, which he compares with the 

 branchias of Crustacea, a comparison which, he says, 

 " me semble d'autant plus probable, que Latreille n'a 

 pas trouve de traces de stigmates sur les nombreux 

 individus qu'il a eu occasion d' observer." 



In the year 1839 M. I'Abbe Bourlet published his 

 " Memoire sur les Podures."^ He described shortly 

 but with much accuracy their antennae, eyes, and other 

 external characteristics. 



He divided the Linnean genus Podura into five 

 groups, characterised as follows : 



PODUEES. 



Antennes longties de trois 



articles, le dei-nier beaucoiip 



plus long que les autres, yeus 

 j formes de six ocelles . . ler genre, Macrotome. 

 j Antennes courtes, de quatre 

 (^articles, liuit ocelles . . 2e genre, Lepidocyrte. 



Coiivertes 

 d'ecailles. 



Sans 

 ecailles. 



Antennes de longueur mo- 

 yenne, variant de deux a. cinq 

 articles inegaux, six ocelles . 



Antennes courtes, constam- 

 nient de quatre articles a pen 

 pres egaux entre eus, dix ou 

 huit ocelles .... 



Antennes tres-courtes, de 

 quati'e articles, corps noir, fort 

 petit, organ du saut attache 

 sous le ventre, et non a son 

 extremite, liuit ocelles . 



3e genre, Heierotome. 



4e genre, Isotome. 



5e genre, Syjpogastrure. 



His genus Macrotoma contains the old species P. 

 jjlumhea, and agrees with Burmeister's Glioreutes and 

 Nicolet's Tomocerus. M. Bourlet was mistaken in 

 supposing that the species forming this genus have 

 only three segments to the antennas. There are 

 normally four, but one is very often wanting, 

 these organs being extremely liable to injury, and the 

 terminal segment, if once removed, being never replaced. 

 This liability to injury on the part of the antennjB has 

 led him into another curious error. The genus Hetero- 



^ ' Mcmoires de la Societe Royale des Sciences, de rAgrieulture ct des 

 Arts, de Lille.' 



