112 ORTHOPTEROUS GROUP INSARAE 



{Arethaea sellata Rehn = A. carita, d" ) 



Arethaea hrevicauda (Scudder) 



Arethaea limifera n. sp. 



Arethaea phantasina n. sp. 

 The only types belonging to the genus which we have not ex- 

 amined are those of A. multiramosa and constricta Brunner, both 

 of which names have been placed without difficulty. 



Key to the Species op the Genus Arethaea 



The present key is admittedly artificial, as it is impossible to 

 express in such shape the shades of difference in proportions and 

 other relative features, which make up the majority of the differ- 

 ential characters in this genus, and which would have to be used 

 in a truly natural key. In consequence the emphasis here placed 

 on many of the differential features is by no means a true index to 

 their natural, or taxonomic, value. The sequence of the species 

 groups and their natural affinities have already been discussed. 

 Female specimens are considerably more difficult to assign satis- 

 factorily than are the males, possessing as the latter do the highly 

 characteristic stridulating field of the tegmina. 



In the case of the female sex of araclmopyga it has been necessary 

 to make a separate entry, distinct from the male sex, but in all of 

 the other forms the two sexes are treated in unit alternatives. We 

 would strongly recommend that the figures illustrating the charac- 

 ters of the species be consulted in connection with the key. 



A. Stridulating field of the male tegmina very broad proximad, with its 



greatest breadth subequal to or but little less than the length of the same 



area, apex of the stridulating vein decidedly or excessively produced; 



tegmina of female shorter than or but little exceeding the length of the 



• pronotal disk. Cerci of the male not strongly bent inwards distad. 



B. Male tegmina with stridulating field proportionately narrowed 

 proximad, distal margin of apical process of stridulating vein not 

 as long as the width of the speculum; proximo-dorsal abdominal 

 segment of male without a dorsal process. Female tegmina slightly 



longer than the pronotal disk carita Scudder 



BB. Male tegmina with stridulating field proportionately broader 

 proximad, distal margin of apical process of stridulating vein as long 

 as {hrevicauda) or longer than ilimijera) the width of the speculum. 

 Proximo-dorsal abdominal segment of male with a dorsal process. 

 Female tegmina distinctly shorter than the pronotal disk (female 

 of limifera unknown). 



