4 Annals Entomological Society of America [Vol. XV, 



opens, the latter being sometimes borne upon a penis, sometimes 

 not. The structure which he thus designates as dorsal and 

 ventral valves are not always, in my opinion, homologous 

 in these various groups, nor even, in many cases, within the 

 Orthoptera, s. s. The basis for this opinion will be evident 

 after the discussion of the various orders. 



The parameres are frequently sunk into invaginations of the 

 body wall, or a common invagination (most Orthoptera), from 

 which they can usually be protruded. The infoldings thus 

 formed may be considerably prolonged into the haemocoele as 

 chitinized apophyses for the insertion of muscles, and some- 

 times only the invaginations and apophyses are present, the 

 freely projecting part of the parameres having disappeared, 

 or secondary processes may develop from the walls of the 

 invagination. In the Blattoidea, Mantoidea, Grylloblattoidea 

 and Phasmoidea the genital aperture, which may or may not 

 be borne upon a penis, lies between two asymmetrical lateral 

 lobes, which apparently represent the parameres, and I have 

 therefore termed them paramere lobes. They usually bear at 

 least one chitinous process, and where several occur, one appears 

 to be the main process, the others accessory parts. I have, as a 

 general rule, considered the main process to represent the 

 terminal part of the true parameres, but this is to be regarded 

 as merely a tentative hypothesis. Possibly a comparative 

 study of the musculature will throw some light on the homologies 

 of these puzzling structures. In the Blattids there is often but 

 one well-developed process on each side, one of these, right or 

 left, being modified into a strong copulatory hook, which can 

 be completely retracted into a membranous sheath. 



Between the base of the penis and the paraprocts (laminae 

 subanales) there is present in some groups (many Phasmoidea 

 and Orthoptera, some Ephemerida) another sclerite, having 

 the form of a more or less projecting plate. It is by no means 

 evident, however, that the plates situated here in these different 

 groups are homologous structures, and it therefore seems hardly 

 justifiable to designate them by a common term. In the 

 Phasmoidea we have the "vomer sous-anal" of Pantel, which 

 this author regarded as belonging to the 10th sternum, but 

 which, in my opinion, probably arises from the membrane 

 between the ninth and tenth sterna. It projects caudad and 

 appears to form a fourth anal valve. In Callibaetis ferriigineiis 



