34 Mouth in Cuphophthalmi 



account of its narrowness, except by dissection'. For this reason the existence of a labrum 

 in these animals has been denied by Thorell (c, p. 29 ; /, p. 765). 



The firmly chitinized part of the maxillary lobes of the first pair of coxae can hardly be 

 described as separated from coxa ; in Stylocellus it appears in the shape of a narrow very 

 low ridge (PI. I., fig. 1 A) on coxa proper. The soft, terminal portion of the maxillary lobe 

 is divided into portions by narrow but deep incisions. Of such portions there are two in 

 Sironini (several figures on PL IV. and V.), three in Stylocellus (several figures on PI. I. and II.); 

 it is onlj' in Ogovia (PI. III., fig. 1 d) that we have been unable to ascertain their existence ; 

 but in the only specimen of this animal which we have had an opportunity of examining, the 

 rather large anterior soft part of the maxillary lobe had collapsed. The foremost of these 

 divisions is always narrow and stretches forward along the outside of the distal portion of the 

 mandibles in such wise that the maxillary lobes of the first pair of coxae embrace the 

 mandibles posteriorly and on the sides. So far the arrangement is the same in Cyphoph- 

 thalmi as in the other sub-orders, but in the former the lobes envelop a greater length of 

 the terminal portion of the mandibles than in the latter, though not to the same extent in 

 all Cyphophthalmi. In Ogovia (PL III., fig. 1 rf) the soft part of the maxillary lobes scarcely 

 reaches the middle of the outer side of the mandibles, when these are seen straight from 

 beneath ; but in the other genera it reaches somewhat beyond the middle, or even nearly to 

 the anterior extremity. The middle and the posterior divisions of the soft part of the 

 maxillary lobes or the posterior division, if there are but two, on either side meet the corre- 

 sponding division on the other side in the middle line behind the mandibles ; they are always 

 broader and shorter than the anterior division ; in Siro and Parasiro the hindmost division 

 is plainly distinguishable (several figures on PL IV. and V.), whilst the foremost appears as 

 a very narrow strip, which is discovered only with some difficulty. Where three divisions are found 

 the hindmost is the smallest of them. Siro and Parasiro differ from the other genera in 

 this particular, that the soft part of the maxillary lobe of the first coxa does not reach back 

 quite so far as the proximal extremity of the latter, as it does, on the contrary, in the other 

 genera, where consequently the soft part of the mouth reaches back to the maxillary lobes 

 of the second pair of coxse. 



A labium sternale does not exist in Cyphophthalmi. What Sorensen {d, p. 5.59) has 

 considered as such in Siro duricorius is the hindmost pair of the soft division of the first pair 

 of maxillary lobes in connection with the part of coxae which is situated just behind. 



The maxillary lobes of the second pair of coxaj have hitherto been recognized only by 

 Thorelll Sorensen denied their existence in StVo {d, p. 5.59), but they occur in all the genera, 

 though with certain differences. In Stylocellini (PI. I., fig. 1 I, lex'-, and several other figures 

 in PL I. and II.) their principal direction follows the longitudinal axis of the animal, and they 

 form a very obtu.se angle with carinae stomothecae ; but m Sironini (PL ill,, IV. and V., 

 several figures) their main direction lies rather across the longitudinal a.xis of the animal, and 



1 We have accordingly been unable to make it visible credidi." Their existence in Stylocellus is indicated in the 



in our illustrations of the mouth in the different genera, following words (ibid. p. 27), " quae duae costae [carinae 



except in Pettalus. Moreover the spot in question is often stomothecae nobis] postice callis duobus parvis, e margiue 



obscured by a deep shadow. basali coxarum 2'" pans formatis, anteriora versus divari- 



' In treating of Siro corsicus Thorell mentions them cautibus, V parvum fere formantibus et paene ad aperturam 



{c, p. 24, note 2) in these words: "coxae 2'" paris turn genitalem pertinentibus continuautur, cum iis stomothecam 



suturam obsoletam versus basin ostendunt, quae suturae limitautes.'' — A long time after we had written this section 



laminas duas (partes coxarum basales) limitant: has laminas the lobes in question were seen in StyloceUiis by Borner. 

 lobos maxillarum pedum 2'" paris loc. cit. (num recte?) 



