96 On Names applied to the British Hemiptera Heteroptera. 



aecker and Barensprmig, as well as Prof, Westwood, adopt 

 the older name, with T. maura as the type. Asojnis, Bur- 

 meister (a collective name for genera not otherwise admitted 

 by its author), having for its type the well-known Zicrona 

 ccerulea, is limited by Dr. Fieber to one of the three species 

 forming Hahn's genus Arma — A. lurida-, by Barensprung it 

 is applied to Cimex punctatus, Linn. [Rhacognathus^ Fieb.), a 

 British species, and by Dohrn to two extra-European forms, 

 Fieber, in his generic table, uses the word " Podisus,^^ which 

 would have been unobjectionable if the genus (which is very 

 slightly differentiated from Arma by the comparative length 

 of the joints of the antennge) is to stand ; it does not, however, 

 seem likely to do so. 



As examples of the second principle, I may mention the 

 following : — 1. Ht/p^iojyhilus , a new name for the combined 

 genera Mac7'odema and Ischnocoris^ neither of which appears to 

 be satisfactorily differentiated from Pterotmetus^ Amy. & Serv. ; 

 indeed Dr, Dohrn (erroneously, I think) includes them under 

 Rhyjyarochromus. 2, Lopomorplms^ combining Acetropis (in 

 pt.) and Leptoptterna, Fieb. 3. Litosoma, a collective name 

 for four of Fieber's genera. 4. Sphi/racephalus (since changed, 

 the name having been preoccupied) for two more genera. 

 5, Idolocoris, the same. It would also be satisfactory to know 

 why Mr. Scott's Monosynamma was discarded for Neocoris, 

 and Macrop)hysa, Westw., was rejected for the later name of 

 Zygonotus. Whether^ ??oc7a/ji(s ?aidiHalticus should be changed 

 because of a prior vl?fot?a/?e and Haltiea, respectively, is a matter 

 of opinion ; if the objection is a valid one, then numerous changes 

 in all branches of natural history are inevitable — the change of 

 three at least of Messrs. Douglas and Scott's above-mentioned 

 genera among them {Hypnophilus^ Litosoma^ and Neocoris). 



Another most unaccountable perversity is the substitution 

 by so many entomologists of Hydrometra for Gerris. The 

 latter name was first used by Fabricius in 1794 (Ent. Syst.) ; 

 in 1796 Latreille, in his ' Precis,' separated one of the species 

 [Gimex stagnorum^lAxm.) under the name oi Hydrometra'^ \ 

 and this genus was afterwards more systematically treated in 

 his ' Histoire ' (1802). But in 1803 Fabricius (Syst. Khyng.) 

 quietly appropriates this name for the greater part of the spe- 

 cies which he had formerly placed under Gerris^ the latter 

 being reserved for a few, mostly exotic f species. He still, 



* Gerris is very clearly separated {inter alia) from Hydrometra by the 

 " four posterior legs long, the anterior short " (p. 86). 



t One common European species (now Ploearia vagabunda) was retained 

 in the altered condition oiGerris, and, according to the general rule alluded 

 to above, this was considered by Burraeister to represent the true Gerris 



