MR. LUBBOCK ON THE THYSANURA. 433 



The account given by Latreille himself is little more satisfactory. " La levre inf^rieure," 

 he says, " se compose de deux petites lames longitudinales, paralleles, avec trois ou quatre 

 divisions setacees, au bord superieur de chaque, et dont I'une est peut-etre un palpe. 

 Quelques autres pieces, et qui, a en juger par la couleur brune, ou tirant sur celle de la 

 corne, de leur extremite, sont probablement les mandibules et les machoires, remplissent 

 les cot6s. J'ai aper9u, a chacun d'eux, un petit corps arrondi, portant une soie, et que 

 je presume etre un palpe maxillaire. Le centre de la bouche est mou, vesiculeux, et 

 cintre superieurement par le labre. J'ai souvent examine, avec une grande attention, la 

 bouche de ces insectes etant encore en vie : je n'en ai vu saiUir auctme partie, et il m'a ete 

 impossible d'en determiner, avec certitude, I'organisation. J'ai consulte anciennement 

 sur cet objet mon ami Savigny, et je me rappelle qu'il me repondit qu'il n'avait pas ete 

 plus heureux que moi." 



This description is vague as well as inaccurate, and was evidently written in haste, as 

 Latreille could not have intended to attribute to mandibles the possession of maxillary 

 palpi. I quote the passage, however, because, if I have myself fallen into error, I may 

 well be excused for having misunderstood a structure which baffled Latreille and even the 

 illustrious Savigny himself. 



However this may be, the mandibles and maxilla are easy enough to identify, and this 

 has been correctly done by Nicolet and Bourlet. The latter, whose second memoir I have 

 as yet been unfortunately unable to obtain, distinguishes (according to M. Gervais, Suites 

 a Buffon, Apteres, vol. iii. p. 382), 1°, ITn epistome paraissant arrondi ; 2°, un labre mem- 

 braneux, en carre long, entier et cache ; 3°, des mandibules ; 4", des machoires ; 5°, un 

 menton ovale ; 6°, une languette large, saillante, ciliee, a deux divisions, chacune de ces 

 divisions quadrifide ; T, des palpes maxiUaires et des palpes labiaux, mais seulement 

 rudimentaires." 



This description is not altogether correct as regards the Smynthuridse, nor does M. 

 Gervais state which species was examined by M. Bourlet, or how far the description is 

 considered by that author as applicable to all the Poduridse. 



M. Nicolet's description of the mouth in the Poduridse is as follows : — " Bouche in- 

 complete, composee d'un labre, de deux mandibules, deux machoires et d'une levre ; point 

 de palpes." I do not quite understand what M. Nicolet means when he calls the mouth 

 " incomplete," nor is he correct as to the absence of palpi. He has, however, been fol- 

 lowed by most succeeding writers. (See, for instance, v. Siebold's 'Anatomy of the 

 Invertebrata.') 



The true composition of the mouth-parts appears to me to be the following : — 1st, an 

 upper lip ; 2nd, a pair of mandibles ; 3rd, a pair of maxillse ; 4th, a pair of small palpi ; 

 5th, a pair of organs probably homologous with the second maxillae ; 6th, a central organ, 

 corresponding to the so-called "langue v^siculeuse" in the Lepismidaj; 7th, the lower lip. 



The labrum is a simple, entire, quadrate, horny lobe, somewhat broader at the base 

 than at the apex, with a few scattered hairs, and a row of teeth at a little distance from 

 the free border, those on each side being parallel and opposite, so that they all point 

 inwards. 



The mandibles are rather small, and differ somewhat from one another (PL XLV. 



3 N 2 



