314 Annals Entomological Society of America [Vol. XII, 



segments eight and nine in Machilis are thus composed chiefly 

 of the coxites, the sternite having practically disappeared. 

 In some of the Lepismatidse, however, (Nicoletia, Atelura) 

 (Escherich, '05)-" the ninth segment has a distinct sternite 

 overlapping the bases of the coxites just as in the thoracic 

 segments. Comparing the eighth and ninth sterna of Machilis 

 with those of the immature Blattid (Figs. 56-59) we have no 

 difficulty in recognizing the coxites of segment nine in the flat 

 stylus-bearing "lobes, which become the dorsal valvulae, and 

 the gonapophyses of the same segment in the inner valvulse 

 of the Blattid, while the gonapophyses of segment eight in 

 Machilis are the homologues of the ventral valvulae of the 

 Blattid. The styli of the latter segment have disappeared and 

 the coxites are fused with the sternite, to form a " coxosternum " 

 (Verhoeff, loc. cit.). It may be added that in Machilis, Lepisma, 

 etc., the coxites of segment nine overlap the gonapophyses, 

 forming a sort of sheath for them, just as they do in such 

 Odonata as have retained a well-developed ovipositor. In 

 Aeshna, e. g., (Fig. 71), the "genital valves" are the coxites 

 of segment nine or dor.sal valvulae, and although more complex 

 in form they have a very similar general position to those of 

 Machilis, covering the other valvulas in the same way, and 

 bearing styli at their apices. There is no part of the anterior 

 gonapophyses of Machilis that is distinctly recognizable as the 

 basivalvulae. " 



The homologies of the terminal abdominal structures of the 

 female with those of the male, and other general questions will 

 be discussed in Part II. 



22 Escherich, K. Das System der Lepismatiden, Zoologica, Bd. 18, Heft 43, 

 pp. 1-164, 11 Pis. and 67 text figures (1905). 



