1960 ] 
Chris tinmen 
Genus Pseudosinella 
5 
P. spinosa , has gone through extensive evolution within the caves. In 
spite of the diverse origins of the species of this genus the forms are 
normally quite similar. The thorax has a somewhat enlarged second 
segment and the mucro is bidentate with a basal spine. The chaeto- 
taxy is very uniform with macrochaetae on the head being commonly 
numerous only along the antennal bases, between the antennae, and 
on the anterior half of the ventral surface. The mesothorax has a 
series of rows along the anterior margin, and the lateral surface of the 
fourth segment and the last two segments have sparse coverings. 
Scattered macrochaetae and groupings of from two to four odd, 
short, feathered setae and one long filamentous ciliate seta occur on 
the third and fourth abdominal segments (See figure n). The scales 
are hyaline, finely striate and apically rounded. On the whole we 
have an artificial but readily separated genus. 
Key to the Cave Species of Pseudosinella of the United States 
I ) Empodial appendage with a clear wing-like tooth at the end of 
a separate outer lamella 2 
l f ) Empodial appendage with a small outer tooth or toothless 4 
2) Mucro without basal spine P. espanci n. sp. 
2') Mucro with basal spine 3 
3) Unguis with median unpaired inner tooth P. petterseni 
3') Unguis without median unpaired innner tooth P. folsomi 
4) Dens with spines P. spinosa 
4') Dens without spines 5 
5) With eyes 6 
5') Eyeless it 
6) Two or fewer eyes per side 7 
6') Three or more eyes per side 1 ’ 9 
7) All inner ungual teeth small 8 
7') Basal, and sometimes all inner teeth large, two eyes per side 
P. alba 
8) Tenent hair weakly clavate and/or median unpaired inner 
ungual tooth absent P . gisini n. sp. 
8') Tenent hair acuminate, median unpaired inner ungual tooth 
present eyed forms of P. hirsuta 
9) Three eyes per side on two separate eyepatches .... P. sexoculata 
9') Some members of each population with more than three eyes 
per side, always on one eyepatch 10 
10) All inner ungual teeth subequal, typically five eyes per side 
P. dubia n. sp. 
Occasional members of a population with four or more eyes may be eyeless. 
