HARDWICKE'S SCIENCE-GOSSIP. 



207 



amongst nomenclators to erect new genera out of old 

 material, regardless of the fact that the types of older 

 genera -were frequently included in such new genera. 

 For instance, the common flat-bodied dragon-fly, 

 (Libellula depressa), taken by Linne as the type of his 

 genus Libellula, was removed thence by Newman, 

 who erected a new genus for the insect under the 

 title Platetrum. Surely it is better for this species to 

 be allowed to remain the pre-eminent type of the 

 Odonata under its old name. 



What has taken place with regard' to the above- 

 named species has been repeated in the treatment of 

 some few others. Mr. W. F. Kirby writing on the 

 subject, says " Latreille fixed the types of Libellula, 

 -Eshna, and Agrion ; and therefore Leach's subse- 

 quent alterations in their use must be rejected. But 

 to minimise the resulting confusion, the corrected 

 form of the second name (sEschna) has been allowed 

 to stand, as in popular use any addition to sEshna, 

 which is co-typical with Gomphus, Leach, would be 

 productive of ill, though strictly speaking it should 

 perhaps have received a new name." The sole 

 exception I have to this is that in use the names 

 /Eshna and sEschna, being somewhat alike in sound 

 and spelling are liable to be occasionally misapplied, 

 insects belonging to the genus jEshna being placed 

 under sEschna, and vice versa. This objection is not 

 however, a sufficiently weighty one to invalidate the 

 use of these names side by side. 



I come now to the main portion of my subject, and 

 propose to make a series of observations on the 

 entire number of British genera, and of those species 

 that have undergone changes of name, etc. I shall 

 take the genera in the order of their classification 

 to-day. 



Family Libellulid.^. 

 Sub-Family Lieellulin*. 



Libellula depressa, Linne. This insect has for 

 a length of time been known as Platetrum depressum, 

 but the generic name Platetrum has now been dis- 

 carded for the reason given above. 



Leptetrum. This genus, which was established 

 by Newman in 1833, includes the two species of 

 Libellula, quadrimaculata, znAfulva. 



Orthetrum, Newman. This genus stands. It 

 includes the species ccerulescens, and cancellalum. 



LEUCORRHINIA, Brittinger. This genus stands. 

 It includes pect oralis, and dubia. 



Sympetrum, Newman. Mr. Kirby writes of this 

 genus, " Newman's name Sympetrum, to which Dr. 

 Hagen objects because it was published unaccom- 

 panied by a description, in an English periodical 

 unknown to Germany at the time, and was not 

 subsequently used by Newman himself, has two of 

 the strongest claims to be retained instead of Diplax, 

 Charpentier, — firstly, that of nine years priority ; and 

 secondly, of having had a specific type assigned to it 

 at the time of publication, which Diplax had not." 



•S 1 . striolatum is a synonym of S. vulgatum, which 

 stands. The other British species, meridionale, 

 Fonscolombii, pZaveolum, sanguineum, and Scoticum, 

 stand good. 



Sub-Family Corduliin.e. 



Somatochlora, De Selys Lonchamps. This is a 

 corrected form of Charpentier's name Chlorosoma, 

 which was preoccupied. Cordulia metallica is now 

 placed under this head. 



Cordulia, Leach. This genus is now restricted 

 to the typical species (sEnea) of the sub-family. 



Oxygastra, De Selys Lonchamps. Cordulia 

 Curtisii is now placed under this head. 



Family /EshniDzE.. 



Sub-Family Gomph.in.iE. 



Division Gomphina. 



Lindenia, De Haan. The species, known until 

 recently as Gomphus (Onychogomphus") forcipatus, is 

 now placed in this genus, which has a priority over 

 Onychogomphus of twenty-eight years. Its new 

 generic name necessitates a change of termination in 

 the specific name, so that the species is now to be 

 called forcipata. 



iEsHNA, Fabricius. This is the genus Gomphus, 

 of Leach, who perverted its use. It includes 

 Gomphus vulgatissimus (now vulgatissima) and G. 

 Jlavipes, and has a priority of forty years over the 

 name Gomphus. 



Division Cordulegastrina. 



Cordulegaster, Leach. This genus, with its 

 species annulatus, stands good. 



Sub-Family /ESCHNIN^-E. 



Anax, Leach. This genus stands, As regards 

 the one British species known as formosus, Mr. 

 Kirby thinks that the name should sink, and Imperator, 

 Leach, take its place, as, although the latter name 

 was published without a description of the species, 

 " the characters of the genus, combined with the 

 locality, are sufficient to identify the species intended." 

 Leach's name has, besides, a priority of eight years 

 beyond that of Van der Linden, so that the species 

 must henceforth be known by its original name^rax 

 imperator. 



Brachytron, Evans. This genus stands. The 

 sole British species pratense, of Miiller, should 

 strictly be known as hafniense. B. hafniense is the 

 female, and is described on page 61 of MLiller's 

 "Fauna Fridrichsdalina," whilst the male, pratense, 

 is described on page 62. I think in such a case the 

 name of the male may be allowed to stand. 



jEschna, Fabricius. This genus stands good, but 

 many changes have taken place in the nomenclature 

 of the species. The name /E. coluberculus, Harris, 

 has a priority of twenty-three years over sE. mixta 



