150 Prof. J. Wood-Masou's Morpholocjical Notes 



the mandible more or less distinctly, and the apical one of 

 the two is continuous with the outer margin of the fleshy 

 setulose flap that projects from the inner margin of the 

 jaw in all BlattidcB ; moreover, the part from which the 

 ball-shaped condyle is given off" is indicated as a separate 

 piece by a distinct inflection of the integument ; so that, 

 counting this last as the first, the two folds as the second 

 and third, and the part of the mandible that succeeds 

 these, and that becomes firmly chitinized at the same time 

 as the condyle, namely, the cutting and crushing apical 

 part, as the fourth joint, we have indicated in the mandible 

 of this embryo cockroach the same number of joints as in 

 that of Chilognathous myriopods, or one less than in that 

 of Macliilis, in which the second, answering to the second 

 and third of the myriopod and to the two folds in Panesthia, 

 may have resulted from the coalescence of two primitively 

 distinct joints. 



The setulose flap above-mentioned seems rather to be a 

 mere process of the third segment than a distinct part, 

 such as an endopodite, and it is, besides, quite unrepre- 

 sented in the far less modified Machilis ; its apex, in 

 embryo as in adult, is received into a notch specially ]3ro- 

 vided for it in the proximal end of the molar process. It 

 is present as a minute, white, fleshy, naked, and obviously 

 viseless rudiment in the nearly related and only slightly 

 more specialized MantidcB, but, so far as I have yet dis- 

 covered, in no other Orthoptera,* nor in any Neuroptera, 

 except, perhaps, Termes. 



In both 'larva3' and adults o^ Panesthia Javanica a 

 faint groove crosses the 'back' of the mandible at the 

 base; in this Oriental species, eight abdominal terga only 

 are in both sexes visible fr-om above without dissection ; 

 but some South American forms are so far less modified 

 than this as to have, in the male, at any rate, ten, the 

 full number of terga externally visible, and it is a signifi- 

 cant fact that, in the only one of these I have as yet had 

 an opportunity of examining, the groove is deeper, and at 

 bottom of much lighter coloration than the surrounding 

 chitine. This groove appears to be the remains of the 

 joint between the third and apical segments of the for- 

 merly four-segmented mandibles. 



* Of these, the Pliasmuhp, at any rate, would appear to differ from the 

 Mantlda and Blattidce in that, in the female, the openin<j of the uro- 

 genital chamber lies between the tenth tcrgum and the eighth, instead of 

 the seventh, sternum, and in the male between the tenth tergum and the 

 tenth, instead of the ninth, sternum. 



