Odonata in the British Museum. 449 



(Natural History), but the authorship and date of the supple- 

 mentary descriptions with which it abounds are unknown 

 to me. Several manuscript additions to the genus Libellula 

 have been ^lade, and among them is the following : — 



" lata. LIB. alis planis hyalinis fascia maculaque baseos 

 nigro - t'usca, abdomiue carinato glauco. 

 Mscr* 

 Hab. in Pensylvania, Marylandia, Carolina." 



These words, however, while agreeing sufficiently well with 

 the male of L. lydia, do not apply to the Fabrician specimen, 

 which is a female of that species. 



Tliere seems to be some reason for believing that Libellula 

 hifasciata, F., usually identified with L. pulchella, Drury, 

 may be, in reality, the ? of L. lydia, Drury. The last- 

 named insect is very different in its wing-markings from its 

 corresponding ^ , which is undoubtedly the L. trimacidata of 

 De Geer and Fabricius, but is very like L. pidchella, and 

 especially the $ of tiiat species. It is true that in 1793 

 Fabricius identified his L. hifasciata^ 1775, both with Drury's 

 figure of L. pidc/tella and also with Petiver's figure (Gazo- 

 phylaciuni, i. pi. xv. fig. 2) of what is clearly intended for 

 L. lydia, ? . This is, however, evidently a case of confusion, 

 due to the similar appearance of the two insects, and the 

 difference in size was overlooked. But it is a very significant 

 fact that Fabricius compares both hifasciata and trimacidata, 

 in respect of build and size, with L. depressa, Linn., and it 

 may be more natural to look upon them as the ? and (^, 

 respectively, of the same species, L. lydia, than to regard 

 hifasciata as L. indchella, which is decidedly larger than 

 L. depressa, and trimacidata as L. lydia, <J , which is rather 

 smaller than L. depressa. 



The fact that the specimen under consideration undoubtedly 

 belongs to trimacidata, and is the only one of the kind in the 

 British Museum which possesses any label in Fabricius's 

 handwriting, would lead one to suppose that it is really the 

 type of his description of that species. But this view of the 

 matter seems to be negatived, both by the description itself, 

 and by the two figures (De Geer, Mem. Ins. iii. pi. xxvi. 

 fig. 2, and Petiver, Gazoph. i. pi. xv. fig. 1) cited in illustra- 

 tion of it, all of which apply to the male sex alone. 



(2) Libellula vibrans, F. ? . Type. 



Labels : — " Libellula vibrans Fab. '' ; " Georgia.'" 

 Diagnosis: — '*L. alis planis albis : macula media atra 



