294 Mr. Westwood on Diopsis, 



such had been the case, because he did not overlook the difference in colour 

 of the thoracic spines. Further, the engraving ought not to be too much 

 relied upon, since the base of the abdomen is nearly as darkly coloured as the 

 terminal segments, and, as Dalman observes, the 4th and 5th longitudinal 

 nerves are represented as running in a straight direction to the margin of the 

 wing. In the last place, Dalman describes the halteres as " pallidi," although 

 Linnaeus is silent as to their colour. 



I have been thus minute in noticing the characters of this species, not only 

 because it is the original and typical insect in the genus, but also because 

 upon the elucidation of its distinctions depends the specific rank of one, if not 

 of two, of the other species which I have given. D. Ichneuinonea does not 

 exist in the Linnsean cabinet ; the only species contained therein being that 

 which I have named D. obscura, and which totally disagrees with the Linnaean 

 description. 



The doubts which exist respecting the characters of this species are more- 

 over increased by those concerning its real habitat. Linnaeus merely says, 

 " Inclitissimo Lond. Anglorum Medico Dom. Doctori Fothergill, qui naturae 

 pervestigationem in summis habet deliciis, et maximam insectorum copiam, 

 prcBclpue ex America septemtrionali et Guinea allatam, possidet, ad Nob. Dom. 

 Praesidem excellentissimas suas coUectiones, baud ita pridem, mittere placuit." 

 The introduction of the word " praecipue" at once shows that the insects in 

 Dr. Fothergill's collection were not exclusively from North America and 

 Guinea, as recorded by Dalman and Wiedemann. Fuessly (according to 

 Donovan) upon this ambiguous authority describes the insect as a native of 

 Cayenne ; Gmelin notes it as inhabiting both Guinea and America ; Fabricius 

 (probably, however, confusing three different species,) mentions Angola, Su- 

 matra, and Congo ; Latreille, on the authority of M. Perrin, a zealous natu- 

 ralist of Bourdeaux, states it to be from the coast of Angola*; Donovan (evi- 

 dently, however, speaking of a distinct species, notwithstanding his positive 



* Latreille, in the Diet. d'Hist. Nat., published an original description of the specimen brought 

 from Angola by Perrin. He describes it as 5 lines long, with the head " fauve," thorax black, ab- 

 domen " fauve," with the two last segments black, wings " avec un point noiratre vers I'extrAnite;" 

 thus confirming the Linnaean description in every particular, as well as establishing its locality as an 

 African insect. 



