MR. LUBBOCK ON THE THYSANURA. 433 
The account given by Latreille himself is little more satisfactory. " La levre infenVure," 
he says, " se compose de deux petites lames longitudinales, paralleles, avcc trois ou quatre 
divisions setacees, au bord superieur de chaque, et dont Tune est peat-el re 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 cotes. J'ai apercu, 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, v&siculeux, 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 saillir aucune partie, et il m'a ete* 
impossible d'en determiner, avec certitude, 1 
»* 
J'ai consults anciennemem 
sur cet objet mon ami Savigny, et je me rappelle qu'il me repondit qu'il n'avait pas 6U 
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°, Fn 6pistome 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; 7°, des palpes maxillaires et des palpes labiaux, mais seulement 
rudimentaires." 
This description is not altogether correct as regards the Smynthuridae, 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 Poduridae. 
M. Nicolet's description of the mouth in the Poduridae 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. Kicolet 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 maxillae ; 4th, a pair of small palpi ; 
5 th, a pair of organs probably homologous with the second maxillae ; Cth, a central organ, 
corresponding to the so-called " langue vesiculeuse " in the Lepismidae ; 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 (PI. XLV. 
3x2 
