430 Dr. H. J. Hansen on the Morphology of the 



latter throughout almost the whole of its length is connected 

 with the lateral wall of the head. Consequently the man- 

 dibles and maxillffi do not really lie within the head at all, 

 but, as in the case of Machih's, are attached to the integument 

 of its sides, which has here become thin and smooth ; and 

 since the articular region of the inner lobes of the maxillas 

 and labium has undergone elongation, we understand how the 

 reduplicature can extend almost as far as the end of the 

 labium. (The necessary investigation is difficult, since the 

 integument on the inner side of the reduplicature and on tlie 

 portion of the lateral wall of the head which is covered by 

 the reduplicature is very thin.) 



37. The musculature of the mandibles resembles that of 

 the Crustacea even more than it resembles the musculature of 

 MacMlis. It is only necessary to compare Meinert's iigure of 

 Japyx with my figure of Diastylis Goodsiri in " Dijmphna- 

 Togtet " (I have only reproduced the three largest muscles or 

 their tendons), or with Sars's figure of Diastylis sculpla^ to be 

 struck by the astonishing agreement in the form and direction 

 of the muscles and of the large median muscle-plate. The 

 mandibles are without a pars molaris, but, on the other hand, 

 we find in Campodea a small lacinia mobilis. 



38. The maxillge consist of a cardo and second segment, 

 which (as in Machilis) is continued into a lobe exhibiting a 

 transverse segmentation in tiie neighbourhood of the tip. On 

 the other hand, the third segment and tiie palpus are entirely 

 wanting. What is termed by authors the outer lobe and 

 palpus is not connected with the maxillae (see especially 

 Stummer-Traunfels, '' Vergleichende Untersuchungen iiber 

 die Mundwerkzeuge der Thysanuren und Collembolen," 

 Sitzungsber. k. Akad. Wiss., math.-naturw. CI,, c. Bd., iv. 

 Heft, Wien, 1891, Taf. i. figs. 7, 10, 11) and does not 

 belong to them, but is, on the contrary, united to the 

 '■' paraglossse " and to the underside of the skeleton of the head 

 which is covered by the labium. 



39. In Jopyx soli/iiyvs the hypopharynx is short and 

 rounded off; the firm cliitin of the " paraglosste " is articu- 

 lated to the chitin of the head behind the base of the hypo- 

 pharynx. The paraglossai themselves lie in front of the latter 

 and coalesce with it for a certain distance ; each of tliese 

 '^ secondary tongues " is on the outer side connected by means 

 of firm chitin with the outer lobe alluded to in § 38, and with 

 a distinct three-jointed palpus. This entire structure, which 

 lies in front of the maxillse, constitutes the conspicuous and, 

 in their basal portions, somewhat abnormally constructed 

 maxillulae. The inner lobe is the " paraglossse " ; the other 

 two portions become the outer lobe and palpus. In the 



