Dr. Baird on the Capture of Sericomyia borealis. 69 



but on the eminence where we found the fly, it was cool and 

 comfortable. There were two cairns, one on the very summit of 

 the hill, the other a little lower down. These flies were found 

 by us on both the cairns, but nowhere else, though in our de- 

 scent we kept a good look-out for them till we reached the base 

 of the mountain. 



The subject of this notice belongs to the genus Sericomyia of 

 Meigen*, one of the family Syrphidce, a family composed of va- 

 rious members of the genus Musca of Linnseus. A species of 

 fly nearly resembling this was described by Linnseus in his 

 1 Fauna Suecica' as an inhabitant of Lapland, and called by him 

 Musca lappona. De Geer, a few years afterwards, figures what he 

 considers the Musca lappona of Linnseus, and describes it at 

 some length under the same name. More lately, Fallen in his 

 ( Diptera Suecise' has noticed, as a native of Scania, the same fly 

 figured by De Geer, and describes it with great circumstan- 

 tiality. Linnseus describes his Musca lappona as having three 

 white bands running across the abdomen. De Geer figures his 

 with four, and describes them as yellow. Fallen retains the 

 name of lappona for the fly with three white bands, and forms 

 another species for the four yellow-banded variety. This he 

 names Syrphus borealis, and in his distinction between the two 

 species he is followed by Zetterstedt and succeeding entomolo- 

 gists. None of these authors, however, make any mention of its 

 possessing the peculiar musical note when at rest I have described 

 above; and perhaps this may be the first time it has been re- 

 corded. 



Fallen in his ' Diptera Suecise/ Syrphici, p. 3, in describing 

 the characters of the family, says : " flores sedulo visitant ; im- 

 primis in arbustis, et in pratis sylvaticis, uliginosis, susurro 

 pipiente, velocissime ssepe volitant ; interdum in aere quasi pen- 

 dentes, totam sylvam, sestate serena, sono sibilante implent." 

 This is a totally different sound, however, from that I have taken 

 notice of as only heard when the fly was at rest and not on the 

 wing. Mr. Westwood, in his admirable ' Classification of Insects/ 

 vol. ii. p. 557, in speaking of the same family, says : " They fly 

 with amazing rapidity, and many delight to hover immoveably 

 over certain spots, to which they will return, if disturbed, for a 

 considerable number of times." He does not take notice of 

 their possessing any peculiar sound ; but in another passage in 

 the same page, he says that he had observed, in experimenting 

 upon the buzzing of some of these insects, " an organ not hitherto 

 noticed, connected with the thoracic organs of respiration, and 

 the instruments whereby the buzzing is produced ; this consists 



* Versuch. ein n. Gattungs d. Eur. zweifl. Ins. in 111. Mag. 1803. 

 B.N.C. VOL. III. N°. II. G 



