258 New Genus of British parasitic Hymenoptera. 



provided ; the antennae of some of the male Mantidoe being 

 only bipectinated, which is also the case in the nocturnal 

 division of the Lepidoptera. A very few Diptera are pro- 

 vided with ramose antennae, as in the genus Ctenophora. In 

 the Hymenoptera this structure is rather more prevalent; but 

 it is almost entirely confined to the stingless division (Tere- 

 brantia LatreiUe) ; although in the genus Psammotherma*, 

 and in a beautiful species of Pompilus, which I have seen in 

 the Royal Museum at Berlin, the antennae are ramose, or, 

 rather, flabellate. In Lophyrus, a genus of saw-flies, the males 

 have a double series of branches, which is also the case in 

 Pterygophorus of Leach. But it is chiefly in the interesting 

 family Chalcididae that we find the greatest number of species 

 having ramose antennae. The genus Chirocerus Latr., and 

 some species of Thoracantha (both belonging to the sub- 

 family Chalcides), are thus distinguished, as well as Eulophus 

 Geoff'roy; in which last-mentioned genus, and in Elasmus, 

 the males have three long slender branches arising from the 

 upper side of the middle joints of the antennae. In my 

 genus Dicladocerus two, and in Pentacladia five, branches are 

 similarly emitted. These four genera belong to the subfamily 

 Eulophides. I have now to describe an insect having four 

 branches, belonging to another division, or subfamily, in 

 which (although various anomalous forms of antennae have 

 been described) no species has yet occurred with ramose or 

 flabellate antennae. 

 Genus, Tetracne v mus Westw. (Tetraknemos, qui quatuor habet radios?) 



Genus quasi intermedium inter Encyrtum et Eulophum. Corpus ob- 

 longum, minutum. Caput thorace paullo angustius. Ocelli distantes. An- 

 tcniitc capite cum thorace longiores; 8-articulatae : articulo lmo, elongato ; 

 2do, parvo, obconico; 3tio, 4to, et 5to, minimis, singulo ramum elongatum 

 supra emittenti ; 6to, longo, tenui, apice supra ramum emittenti ; 7mo, paullo 

 breviorij ultimo, magno, oblongo-ovato. Thorax ut in Encyrtis formatus, 

 scutello magno subrotundato. Ala: 

 anticas nervo subcostali, cum costa 

 spatio parvo conjuncto, et ad apicem 

 ramum parvum clavatum et curva- 

 tum emittente. Pedes sat longi atque 

 graciles, intermedii ut in Encyrto 

 formati. Tarsi 5-articulati pulvillo 

 magno. Abdomen parvum, ovatum, 

 subdepressum; apice subacuminatum. 

 Mas. 



Species unica mibi adhuc cognita. 



Tetracnemus diversicornis Westw. 

 — Caput nigro-aeneum, vcrtice tenu- 

 issime et transverse rugosum. An- 

 tenna: nigra?, pilosae. Thorax aeneus, 



* There are two species of this beautiful genus in the Berlin Museum. 



