Tribe 5. Brachyglutini 



The Brachyglutini is well represented in tropical America by twenty-eight 

 genera out of sixty odd for the world. As with the preceding tribe, following a 

 key to genera, these twenty-eight groups are arranged in linear form, although 

 few phylogenetic relationships can be demonstrated in this way. The arrange- 

 ment of these genera is almost the reverse of the order used by Raff ray (1908). 

 This eminent specialist placed the brachyglutines after the batrisines and 

 metopiines. From what has been said previously on the derivation of the 

 pselaphids from a staphylinoid stock, it appears that the batrisine genera are 

 much less staphylinoid than the Brachyglutini. This is especially obvious when 

 the tendency in Batrisini for the reduction or complete absence of the abdominal 

 margins is contrasted with the generally better developed margins of the 

 Brachyglutini. 



On the other hand, the single tarsal claw of Brachyglutini is less staphy- 

 linoid than the two unequally developed claws of the Batrisini, although the 

 Euplectini have both tarsal claw patterns frequently developed. Again, the first 

 visible sternite in both brachyglutine and batrisine tribes is poorly developed, 

 but less invisible in the latter. Thus, although there are many exceptions in 

 both tribes, we feel that the batrisines are structurally more specialized than 

 brachyglutines. The twenty-eight genera alluded to are arranged here in a series 

 in which the species have progressively less contiguous posterior coxae, the 

 middle coxae are progressively less contiguous, and the abdominal margins are 

 progressively less developed. It should be noted that this is a tendency in the 

 arrangement, and not a complete application since, in many cases, other struc- 

 tural features have altered the relative position of genera in the series. For ex- 

 ample Drasinus and Decarthron are placed near each other, a course which I 

 adopted after examination of my material in both genera, and later discovered 

 that Fletcher (1928) had previously reached the same conclusion. Barada, 

 Eupsenius and Eupsenina begin the series as a consequence of their melbaform 

 affinities, and the approximate posterior coxae in the first two genera is common 

 in the Euplectini but very rare in the Brachyglutini. The remarkable glabrosity 

 of Eupsenius and Eupsenina however precludes considering them as very primi- 

 tive, but it is thought that these genera are more euplectine than many other 

 subglabrous genera and have arisen from euplectoid ancestors which have 

 evolved highly specialized species which exist today. The case for each genus 

 is more or less different, and involves summation of many values, thus the 

 almost marginless, subglobose body of Eupsenina is accompanied by capitate 

 setae on the ventral surface of the head, and many other instances could be cited. 



The chief structural features which combine to distinguish this large tribe 

 are (1) oblique articulation of trochanter and femur of the middle legs, (2) 

 three-segmented tarsi, the first segment of which is relatively minute in con- 



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