226 Journal New York Entomological Society, f^'oi. xxv'. 



Pterygotan insect, is represented by a similar suranal plate in the 

 Lepismids (fig. 2, " ii ") ; although this plate in the Lepismids bears 

 a terminal abdominal filament (fig. 2, t) not present in most Ptery- 

 gotan insects, excepting the Ephemerids. The cercus-bearing podical 

 plate of the lower Pterygotan insects (labeled " p" m figs. 8, 12, 6, 

 etc.) which is apparently a portion of the eleventh segment, is also 

 present in the Lepismids (fig. 2, "p."; the attachment of the cercus 

 is indicated by the letter " c"). The tenth segment, designated by 

 the numeral "10" in figs. 8, 12, and 4, is only slightly less pointed 

 and projecting in the Pterygota there figured, than in the Lepismid 

 depicted in fig. 2. The ninth segment is divided into a dorsal and a 

 ventral portion 9^ and gt in the Pterygotan insect shown in fig. 8, 

 and the same is true of the Lepismid (fig. 2) ; but in the Lepismid, 

 a large stylus, or " megastylus " (fig. 2, " m"), is borne on the ventral 

 plate of the ninth segment of the female, while in the majority of the 

 lower Pterygota (with the exception of the Odonata) such a stylus is 

 retained only on the tenth segment of the male. The dorsal valve 

 of the ovipositor (fig. 5, " d") is borne on the ninth segment, and the 

 ventral valve (fig. 5, "v") is borne on the eighth segment in the 

 lower Pterygota, as in the case in the Lepismids'^ also (fig. 2, "' d" and 

 "v"). It is thus clearly evident that the terminal abdominal struc- 

 tures of the Lepismids are fundamentally and essentially similar to 

 those of the lower Pterygotan insects, and the same is true of the head 

 and other structures, so that Handlirsch's attempt to separate the 

 Apterygota into a class or classes which do not include the Pterygota 

 also, is quite unwarranted, and fails to take into consideration the 

 fundamental resemblances which underlie all true relationships. 



The terminal abdominal structures described above, remain but 

 little modified in the lower Pterygotan insects, and it is rather- sur- 

 prising that they do not give more serviceable clews as to the rela- 

 tionships of the insects here discussed. They do however furnish 

 some indications of relationships which are borne out by the study 

 of other structures, and this would doubtless be even more evident 

 if other more favorable material were available for comparison. 



General usage requires that designations of a Latin or Greek 

 derivation shall be applied in anatomical terminology, so that the 



3 This statement is based on figures of Lepismids by other investigators 

 since I am not sure of the sex of the Lepismid here figured. 



