82
NEUROPTERA.
aishna clavata.
Plate 45. fig. 1.
Family. Libellulid.®, Leach.
Genus. ^Eshna, Fabr. Libellula p. Linn. Donov. Oordulegaster, Leach.
Ch. Sp. IE. abdomine clavato, basi gibbo ; corpore nigro, fusco viridique variegato. Expans,alar. 3J unc.
IEL •with the abdomen clavate gibbose at the base; body black, varied with brownand green ; stigma brown. Expanse of the wings 3J inches.
Syn. ^Ishna clavata, Fabr. Ent. Syst. II. p. 385. Spec. Ins. 1. p. 526. 4.
Linnaeus divides the dragon flies (Libellula, Linn) into two sections :—“ 1. alispatentibus acquiescentes; ” and “2. (alis erectis) oculi distantes remotique.”Fabricius divides the Linnaean Libellulae into three distinct genera; the first retainsthe Linnsean name, the second and the third are called Aeshna and Agrion. Theirmost essential characters are taken from the form and situation of the mouth, andtherefore require a deep magnifier to determine them with accuracy. Donovan states,that he had examined those parts in the greater number of the species Fabricius hasdescribed, and found his characters agree, except in one instance; which Donovannevertheless considered a proof of the impracticability of adopting the whole of hissystem: he describes Libellula Chinensis, and refers to the only figure that has beengiven of it, in one of the plates of Edward’s Natural History of Birds, 1745.* HadFabricius seen and examined this rare species, he must have referred it to his genusAgrion, each of the lips being bifid, or two-cleft, as in Libellula virgo and puella,—the essential characteristic of the genus Agrion ; for the mouths of the Libellulaa ofFabricius differ altogether in structure, and are not notched in the slightest degree,as Libellula clavata, ferruginea, 6-maculata, and the European species, Libelluladepressa, will sufficiently illustrate.
Donovan, however, rejecting the Fabricius generic distribution, states, that Alshnaclavata must be arranged with L. grandis and forcipata; but it is nearer allied toOordulegaster annulatus, Leach (Libellula Boltoni of Donovan’s British Insects.)
* That Fabricius should have erred in the location of a species which he had never seen, but knew onlythrough a rude figure, is not surprising ; but surely such a circumstance can be no proof of the improprietyof a system founded, as Donovan clearly shows, on characters of stability. J. O. W.