GENERAL ORGANIZATION. 205 



One of the most interesting points in the organiza- 

 tion of this group is the possession of subabdominal 

 appendages. 



Machilis maritimus, for instance, has a pair of elon- 

 gated, cyhndrical appendages attached to every seg- 

 ment excepting the first. In Lepisma saccharina, and 

 in lapyx, on the contrary, these appendages are repre- 

 sented by mere groups of stiff hairs. The anterior 

 subabdominal appendages of Nicoletia and of Camjpodea 

 much resemble those of Machilis ; in the former genus 

 they are said by Nicolet ^ to be " accompagnees chacune 

 au cote interne d'un petit corps vesiculeux et ovale faisant 

 probablement partie des organes de la respiration." 



The ovipositor of MacJdlis is composed of four elon- 

 gated, cylindrical, narrow, rod-like appendages, of which 

 the two anterior belong to the eighth (PL LXVI, fig. 6), 

 the two posterior to the ninth (PI. LXVI, fig. 5), seg- 

 ment. In the male there is a broader, shorter, and 

 somewhat spatulate process (PL LXVI, fig. 7) on the 

 under-side of the ninth segment. Latreille observes ^ 

 that the ovipositor " part du dessous du onzieme seg- 

 ment du corps, les trois du thorax compris," and adds 

 that it is " formee comme dans les Tenthredines, les 

 Sauterelles, &c., de deux pieces etroites, allongees, tres 

 comprimees, pointues au bout, appliquees I'une centre 

 I'autre par leur face interne, demi transparentes et 

 garnies de petits polls." In fact, however, it consists 

 of four such slender rods, two belonging to the eighth 

 and two to the ninth abdominal segment. The short 

 description given by Dr. Dickie ^ seems, therefore, to me 

 substantially correct. He says of the rods, however, 

 that they are " slightly club-shaped." They do not 

 appear to me to be either club-shaped or pointed. 



In Lepisma the subabdominal appendages are con- 

 fined to two of the posterior segments, although they 

 are indicated on the anterior segments by groups of 



' ' Ann. Soc. Ent. France,' 1847, p. 353. 



^ ' Nov. Ann. d. Museum,' vol. i. 



3 ' Trans. Britisli Assoc.,' 1855, p. 110. 



