150 ' [July. 



North American Proctotrypidce of the ? of Isohrachium (Forst.), 

 myrmecopliilum, Ashm. The recent appearance of the earlier 

 portions of vol. ix of " Andre's Species des Hymenopteres d'Europe 

 and d'Algerie enables me to place the insect in the genus Fs&udiso- 

 hracliium, Kieff. {Isobracliium, Ashm., nee Forst., the true genus 

 Isohracliium, Forst., has a winged ? , the type being, according to 

 Ashmead, mains fuscicornis^ Nees, but there seems to me to be some 

 mistake about this type). The genus Pseudisohracliium contains, 

 according to Kieffer, 15 species, of which 7 are North American, 

 5 are European, 2 are South American, and 1 Indian. 



In the case of the 5 European species, it has not been possible to 

 associate the sexes, but in the case of 4 American species, both J 

 and ? are known. It is in fact, only as the result of the American 

 discoveries that the 2 European species, of which the ^ (^ are known, 

 are placed in this genus, for they have no resemblance whatever 

 to the 9 $ . All the species probably consort with ants. P. man- 

 dihulare, Ashm., with Camponofus pennsylvanicus, Pergande ; 

 montanum, Ashm., and P. mjjrmecopliilum^ Ashm., with Formica rufi- 

 harhis (Hubbard) ; P. rufiventre, Ashm,, with 'Formica ohscuripes 

 (Ulke) ; and my P. cantianum apparently with Ponera contracta. 

 Ashmead has raised a query whether the insects are parasitic upon 

 the ants or upon the Coleoptera that live with them. I cannot answer 

 this, but the present insect is too large to be parasitic on Machcerites 

 glalratus^ the only Coleopteron that 1 know to live with Ponera. It 

 may be parasitic on a beetle living with another ant, for at Charing 

 almost all the British ground ants occur, and I have taken Homceusa 

 close to the spot where I found it. In this case the resemblance to 

 Ponera would be of use (I presume) in protectino: it from the attacks 

 of other ants. Ponera itself must be somehow protected; it is slow, 

 and though armed with a sting, would seem likely to fall a prey to 

 the hosts of other ants, in the midst of which it lives, and yet it 

 evidentl}^ thrives. 



It ought to be pointed out that there is just a possibility that 

 the insect above described is really the ? of PaeudisohrachiiLm sub- 

 cj/anea, Hal., of which only the ^ is known, but for the present it 

 must be described as distinct. The ^ of suhcyanea has been taken 

 by me at Huntingfield and Doddington and in Sheppey, and I have one 

 specimen labelled Charing ; it occurs in September, it was originally 

 described as Fpyris nigra, West., by Walker from Haliday's MSS. 

 (see Ent. Mag., iv, 432), corrected by Halliday, who then named the 



