Bumble Bees

Studies on Scandinaviqn Bumble Bees 173Hasselrot 1962; Ander 1963, 1965; Frid6n1967. Bombus derhamellus: Dahlbom 1832, p.44 (partim). Bombus sylvarum var. D Thomson,1872; Siebke 1880; Strand 1898b. Bombussylvarum var. nigrescens P€rez, 1879, p. l2l,lectotype ? MNP !, type area the Pyrenees;Gaunitz l93l; Loken 1958b, 1960; Erlandsson1960 ; Kruseman 1960 ; Ander 1963 . Bombusnigrescens P6rez; Kruseman 1958b ; Faester 1959.)First Scandinavian recordsNorway. Akershus: Oslo (Siebke 1880).Sweden Uppland (Linnaeus 176l).have some pale hairs on episternum and/or thefirst tergite, and one worker displays a pronouncedintermediate colouring. The designationnigrescens P6rez is, moreover, erroneously usedfor the North-European population but needs noreplacement as far as the melanic form does notqualify for nomenclatural rank.B. sylvArum produces dimorphic infrasubspecificforms with sympatric occurrence not only inthe Pyrenees, Scandinavia and Denmark butalso apparcntly in other fringes of its distribution,e.g. in the Caucasus (Schmiedeknecht 1883, p.87 (337)). A few melanic specimens are alsorecorded in England (Mortimer lg22; Yarrow1 959).Taxonomical remarksThe Scandinavian population belongs to thenominate subspecies.oThough Thomson (1872) describes a melanicform as var. b, the dark Swedish individualswere nevertheless later misidentified as .8. ruderariusuntil they were recognized by Gaunitz(1931) and treated as B. ^r. var. nigrescens.Though Siebke (1880) and Strand (1898b) listedvar. b Thomson as occurring in Norway, themelanic specimens were all found under B. ruderariusin the collections when recognizedby Loken(1 958b).P6rez (1879) designated, however, B. ^r. var.nigrescens as the melanic form of the Pyrenees,where it likewise occurs together with nonmelanicforms, and therefore Kruseman (1958b)doubtfullyrecognized it as an endemic species,B. nigrescens. CorrespoRding dimorph forms alsooccur in Denmark where Faester (1959), statingthat intermediates were never observed, likewisegave the melanic form specific rank, B.nigrescens. Ffowever, inhabitants from two B.sylvarum colonies (Sweden: Sk6ne: Norra Nobbelovin Lund 1932 (Kemner) ZML) present bothtypical and melanic forms, which proves theconspecific status. The preserved material consistsof the old Q, 5 VH 4 36 of the typical form and4 melanic HH from one colony while 4 typical Vqand 4 melanic HH from the second colony. Inboth colonies several of the melanic workersQueen, workerMorphological characters. Malar space slightlylonger than distal width, about as long as Asa a.Clypeus hardly longer than distal width; discof clypeus convex with rather flne, dense puncturingexcept for anterior, usually impunctatearea between well-defined lateral impressions,which are rather coarsely punctured. Labral furrowmoderate to well-defined, almost parallelsided,queer (Fig. 224); labral lamella smooth,shining with the edge knife-sharp. Mandibleshort (Fig. 228). Surface of Tn-u smooth,shining with moderate to rather sparse puncturing.Distal keel of St u usually reduced to apoint. Hind basitarsus almost parallel-sided. Coatrather short, rather even.Queen measurements. N - 201' SE Norway;malar space: 0.77 mm (t0.03 +0.01) range:0.70-0.80 mm;'radial length': 3.36 mm (+0.09+0.02) range: 3.15-3.50 mm; interalar width:4.53 mm (+0.13*0.03) range: 4.23-4.78 mm.Body of small to moderate size.Colour pattern Pile of face yellowish-grey,more or less encroached by variable mixture ofblack. Pile of vertex with mixture of yellowishgreyand black, occipital ridge otherwise blackhaired;hairs on head otherwise ranging frommainly grey to predominantly black. Thoraxclothed yellowish-grey with exception of broadinteralar band encroached with yellowish-greyhairs in front, laterally and behind, and additio-12. Bumble Bees.