RELATIONS OF INSECTS TO OTHER ARTHROPODA 13 



FIG. 7. Deutomala of Julus, the 

 lettering as in Fig. 6. 



known, judging by Metschnikoff's work on the embryology of the 



diplopods, these myriopods seem to have in the embryo but two 



pairs of post-antennal mouth-parts, which he designated as the 



"mandibles" and "labium." Meinert, 



however, regards as a third pair of 



mouth-parts or "labium" what in our 



Fig. 7 is called the internal stipes (slip. 



i.), behind which is a triangular plate, 



lamina labialis (lam. lab}, which he re- 



gards as the sternite of the same seg- 



ment. 



The hypopharynx, our "labiella," 



(Fig. 6), with the supporting rods or stili linguales (sti. I), of Mein- 



ert, are of nearly the same shape as 

 in some insects. 



Of the clypeus of insects there 

 is apparently no homologue in 

 myriopods, though in certain dip- 

 lopods there is an interantennal 

 clypeal region. The labium of 

 insects is represented by a short, 

 broad piece, which, however, unlike 

 that of insects, is immovable, and 

 is flanked by a separate piece called 

 the epilabntm (Fig. 8). Vom Rath 



FIG. 8. Hesul of Scolopendru, seen from i n U,p r vp f ] an Piimharvnv whinh 

 beneath, showing the "mandible" (proto- nas OUSeiveU. an eplpnaiyilX, W111C 



v .1 oamp o-pnpval rplif inn<5 <i in 



nas tne same geiieiai relations as in 



mala) with its carrlo (c<ird.) and stipes (*<.), 



also the labrum and epiiabrum. 



insects. 



The embryology of myriopods is in many re- 

 spects like that of insects. The larva of diplopods 

 hatches with but few segments, and with but 

 three pairs of limbs ; but these are not, as in 

 insects, appended to consecutive segments, but in 

 one species the third, and in another, Julus multi- 

 striatus? (Fig. 10), the second, segment from the 

 head is footless, while Vom Rath represents the 

 first segment of an European Blaniulus as footless, 

 the feet being situated consecutively on segments 

 2 to 4. The new segments arise at " the growing 

 point " situated between the last and penultimate 

 segment, growing out in groups of sixes (Newport) 

 or in our Julus multistriatus ? in fives (Fig. 10). In 



Fis. 9. Larva of 

 Julus : a, the 3d ab- 

 dominal segment, with 

 the new limbs just bud- 

 ding out ; b, new seg- 

 ments arising between 

 the penultimate and the 

 last segment. After 

 Newport. 



