THE FINDING OF THE QUEEN OF THE ARMY ANT. 149 



Of the eleven species of insects found in the bivouacking mass 

 of hamatum workers and soldiers nine are Coleoptera, one a large 

 Thysanuran (Atelura sp.) and one a mite resembling Discopoma. 

 The beetles have been studied by Dr. W. M. Mann and Mr. H. S. 

 Barber of the National Museum. The former writes me that 

 there are five species of ecitophiles, namely two Staphylinids 

 and three new species of Histeridae. One of these is a Trog- 

 lostermis, one a Synodites and the third, the remarkable form 

 represented in Fig. 8, has been described by Dr. Mann as 

 Euxenister wheeleri. The four remaining forms are bark- 

 inhabiting or fungus beetles which were evidently brought in 

 as prey by the foraging columns of ants. Mr. Barber identifies 

 the specimens as a species of Staphylinus (sensu lato], two species 

 of Erchomus and a Rhymbus (Endomychidae). He sends the 

 following note concerning the last, of which several specimens 

 were taken : ' ' The Rhymbus seems to be Rh. hemisphcericus Gerst. 

 1858, but not the species treated under that name by Gorham 

 1873 (Biol. C-A) although his piceus is perhaps a synonym of 

 Gerstackers species. Unfortunately an earlier generic and 

 specific name (Bystus coccinelloides Guerin 1857, from Colombia) 

 is listed under Rhymbus Gerst. 1858, and from its original de- 

 scription I cannot see why this latter name should not apply to 

 the Barro Colorado specimens. The species is new to the 

 National Collection.' 



