CLAVIGERINAE 351 



The large abdomen has six sternites, the typical Pselaphid number, but 

 the tergites are specialized: the general tergite pattern is a tergum or dorsum 

 of three fused tergites, and two terminal tergites. The fused dorsum shows 

 its lineage along the lateral margins, where the component tergites have not 

 been wholly fused ; medianly the tergum presents a glabrous expanse which is 

 usually deeply depressed at the base. The antero-lateral angles of the margin 

 of the tergum also usually bears trichomes. Thus the elytral and abdominal 

 trichomes ornament the base of the abdomen. This dorsum, with its trichomes, 

 is paralleled in the less complicated but similar abdomen of the myniiecophilous 

 Attaseniini, so that it is not purely clavigerine. The actual reduction in ab- 

 dominal segments is not peculiar to Clavigerinae, in fact this reduction is 

 suipassed in the Cyathigerini, where Cyathiger has the segments fused to give 

 only two tergites and two sternites. Thus the abdominal features are not unique, 

 and may not be used to separate the two subfamilies. 



The legs are definitely macrosceline; the tarsi are three-segmented, with 

 the first two tarsomeres small and the third tarsomere much larger, elongate- 

 cylindrical, subarcuate, and bearing a single tarsal claw. 



Integumental modification is very diverse, glabrous, punctulate, punctate, 

 granulate, cribrate, alutaceous, or striate. Pubescence is similarly diverse, the 

 setae being elongate-aciculate, subsquamoid, bifurcated (Adranes) , or apically 

 plurifurcate {Claviger, in part). 



Sex is best discovered by direct dissection. The aedeagus is of the tyrine 

 type, with a narrowly oval basal bulb which is bifenestrated, and which 

 terminates apically in a rapidly narrowing, arcuate, sperm-conducting apex. 

 The males often have the sternites longitudinally concave, giving a distinctive 

 lateral profile ; the abdomen is more tapering from a dorsal view, the metaster- 

 num is often secondarily modified by tubercles or cusps, and the legs usually 

 armed by spines or teeth, but not always. Thus males may bear prominent 

 femoral spines, or femoral and tibial spines, or lack spines entirely, in the 

 same genus. Females have the sternites longitudinally convex in profile, the 

 abdomen much more rounded apically from a dorsal view, and the metasternum 

 and legs are simple, or relatively so. 



It is obvious that the clavigerines are, at most, of subfamily rank. The 

 elevation of these species to family status in the Leng (1920, p. 132) catalogue 

 is not tenable unless the Staphylinidae are broken into numerous families 

 and the Pselaphidae are similarly separated into at least five families. Al- 

 though my opinion is derived independently from the comparative morphology 

 of the pselaphids, it should be noted that students of the family give the clavi- 

 gerids subfamily rank (LeConte and Horn, 1883; Brendel and Wickham, 1890, 

 p. 218; Ganglbauer, 1895; Raffray, 1904, 1908, 1911; Mann, 1921; Bruch, 1933; 

 Bowman, 1934; Meixner, in Kukenthal, 1936). 



The comparative ecology of Clavigerinae is in much need of study. They 

 are an example of adaptive speciation within a particular niche, namely the 

 society of ants. They are never free-living — indeed, their rudimentary mouth- 

 parts make it probable that they would be unable to compete with the predators 



