RELATIONS OF INSECTS TO OTHER ARTHROPODA 



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 (stip. 

 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 epilabrum (Fig. 8). Vom Rath 

 has observed an epipharynx, which 

 has the same general relations as in 

 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 FIG. 9. Larva of 



. m , . . Julus : a, the 3d ab- 



to 4. Ihe new segments arise at "the growing dominai segment, with 



, ,, , , , ,, n , . . the new limbs just bud- 



point situated between the last and penultimate ding out; 6, new *eg- 



, r /-VT , \ ments arising between 



Segment, growing Out 111 groups Of Sixes (Newport) the penultimate and the 



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



Stip " M 



