222 NEOTROPICAL PSELAPHIDAE 



only recently pupated. This checks with similar data on other species so that 

 there seems to be a general period of pselaphid pupation in the rain forest 

 floor in the rainy season, during the first half of July. Other periods are to 

 be expected (May 4, 1935 for Barrometopia quasimoda in the nest of its host 

 termite at the end of the dry season is of interest as the dark, humid nest en- 

 vironment is in contrast with the dry season) and it is quite possible that life 

 cycles are begun and completed for the duration of the protracted wet period 

 in the tropics. 



Arthmius sabomba is unrelated to other groups in the genus save the third, 

 and within this group is distantly associated with bubalus. Both sexes promptly 

 diverge from Raffray's 1897 key to males and females, and the recent species 

 of Raffray and Fletcher are equally different. 



In this connection a word should be said as to the identity of unique 

 specimens in the genus. Since many species are known only from one sex, the 

 keys to Arthmius in the present paper will serve to identify males or species 

 represented by both sexes but students with an isolated female will have to 

 take the specimen through each group key, and then consult Raffray's notes 

 of 1897. Even then there is an element of doubt since early descriptions are 

 not complete. 



Key to the Species of Group IV 



Six stemites fully visible (Males) 2 



Five sternites fully visible (Females) 7 



2. Antennal segment I very large, inflated on the ventral face, other 



antennal segments simple ; 2.1 mm bison 



Antennal segment I simple, not conspicuously large and ventrally 

 produced 3 



3. Antennal segment II abnormally large 4 



Antennal segment II not abnormally large 6 



4. Antennal segment II with the dorsal face dilated and with the internal 



face flattened 5 



Antennal segment II not armed or dilated but more than three times 

 longer than segment III, with the internal face rounded, and dorsal 

 face depressed and squamously pubescent; 2.5 mm orion 



5. Antennal segments III, IV, and VI not much longer than wide; V 



and VII much longer; VIII square; IX and X much larger and 



orbicular; 1.8 mm bythinoceros 



Antennal segments IV, V, and VI nearly three times longer than wide ; 



VII much longer than wide; IX and X oval; 2.2-2.4 mm reitteri 



6. Antennal segments V, VI, VII with internal faces slightly rounded, 



slightly larger than IV or VIII; IV and VI square; VIII trans- 

 verse ; 1.8 mm quadripunctatus 



Antennal segment V much larger than IV or VI; VII cylindrical; 



VIII square; 2 mm bituberculatus 



