Scuttle flies (Diptera: Phoridae) reared from logs in Finland and N. W. Russia, including two new species

2019·1.9 MB·

by  R. Henry Disney

©EntomologicaFennica.12February2010
Scuttle flies (Diptera: Phoridae) reared from logs
in Finland and N. W. Russia, including two new species
R.HenryL.Disney
Disney,R.H.L.2009:Scuttleflies(Diptera:Phoridae)rearedfromlogsinFin-
landandN.W.Russia,includingtwonewspecies.—Entomol.Fennica20:257–
267.
NinespeciesofMegaseliaRondanihavebeenrearedfromlogs,inFinlandand
NorthwestRussia.Megaseliaexcorticatasp.n.andM.tignorumsp.n.arede-
scribed,thelatterbeingasiblingspeciesofM.setulipalpisSchmitz,whichwas
alsorearedfromlogs.
Disney, R. H. L., Department of Zoology, University of Cambridge, Downing
Street,CambridgeCB23EJ,U.K;E-mail:[email protected]
Received20November2008,accepted23February2009
1.Introduction rearedfromthesporophoresofseveralspeciesof
fungi(e.g.Disney1994).
McLean(2000)hasreviewedPalaearcticDiptera Duringaninvestigationintothesaproxylicin-
associated with dead wood. Detailed studies of sectscarriedoutbytheFriendshipParkResearch
theirlarvalfeedinghabitsarepatchy,withsome Centre (Kuhmo Regional Environment Centre)
familiesoftenonlylistedatthefamilylevel.The inKuhmo,easternFinland,numbersofPhoridae
scuttleflies(Diptera,Phoridae)areonesuchfam- were obtained from logs placed in emergence
ily. However, in Germany, Büchs (1983, 1988) sacks.Emergedfliesweresortedandsenttothe
studiedthefaunaobtainedinemergencetrapsat- MallochSociety(Scotland)forfurthertreatment
tachedtothetrunksandbranchesoflivingwood- and identification. The specimens of Phoridae
landtreesandidentifiedthePhoridaetothespe- werepassedtomebyDavidRobertson(National
cieslevel.Namedspeciesrearedfromdeadwood MuseumsofScotland).
are limited to a few reports only. These include
Megaseliafungivora(Wood)rearedfrompupae
foundunderthebarkofbeech,rowanandconifer 2.Methods
logsinEngland(Disney1979,1994);M.obscuri-
pennis (Wood) larvae inhabiting rotting wood, 480treesfrom6sites,inFinlandandNorthwest
wheretheyparasitisethelarvaeofSciaridae(Dis- Russia,werefelledin2003.Partsofthesetrees
ney,1980);M.shawiDisneyrearedfromadead wereremovedannuallyandtheseharvestedlogs
willow(Salix)trunk(Disney2006);M.frameata were placed in rearing sacks. The logs were
Schmitz and M. robertsoni Disney reared from sampledfromthebase,midandupper(canopy)
pupae found under the bark of a spruce stump trunkregion,aswellasbranchesseparately (G.
(Picea)inNorway(Disney2008)andTriphleba Várkonyipersonalcommunication).Theemerg-
gracilis(Wood)rearedfrompupaefoundunder ing insects were collected, preserved in alcohol
thebarkoffallentrees(LarixdeciduaandPicea and subsequently mounted on slides in Berlese
abies) (Disney 1979). M. frameata has been Fluid (Disney 2001). A holotype from the
258 Disney (cid:127) ENTOMOL.FENNICAVol.20
Fig.1.Megaselia
excorticatasp.n.
–a.Female,abdominal
tergites5–7.–b.Male,
rightpalpfromabove.
–c.Male,rightfaceof
hypopygium.–d.Left
faceofhypopygium.
Scalebars=0.1mm.
Schmitzcollection(MuseumAlexanderKoenig, ported breeding in a rot hole in an oak tree
Bonn)wasremountedinEuparal. (Quercuspetraea)(Godfrey&Disney2002).
Thetreespeciessampledweretremblingas- Male.Fronsbrown,clearlybroaderthanlong,
pen(Populustremula),silverbirch(Betulapen- with40–42hairsanddensefinemicrosetae.Bris-
dula),Scot’spine(Pinussylvestris)andNorway tlearrangementsimilartoFig.2d,withthelower
spruce(Piceaabies). supra-antennals shorter and weaker than upper
pair, but stronger than the longest bristles on
palps. Cheek with three bristles and jowl with
3.Thespecies
two.Theglobosepostpedicelsbrownandwithout
The species obtained were all members of the SPSvesicles.PalpspaleduskyyellowandasFig.
hugegenusMegaseliaRondani.Thekeystothe 1b. Labrum paler than palps and about half as
malesofBritishspecies(Disney1989)andthelit- wide as a postpedicel. Labella also pale, rela-
eraturecitedthereincovermostoftheEuropean tivelynarrow,andwithonlyafewshortspinules
species.However,additionsandamendmentsare below.Thoraxbrown.Threenotopleuralbristles
constantlybeingmade(e.g.Disney2003). andnocleftinfrontofthese.Mesopleuronwith
The specimens are deposited in the Cam- fourhairs.Scutellumwithananteriorpairofhairs
bridgeUniversityMuseumofZoology(CUMZ). (atmostaslargeasthoseinmiddleofscutum)and
Incitingthis,twosetsofnumbersaregiven,e.g. a posterior pair of bristles. Abdominal tergites
(298, CUMZ, 13–73). The 298 refers to the brownwithhairsmainlyinrearthirdsandonlya
sample number the 13–73 refers the author’s littlelongeratrearofT6.Ventergrey,andwitha
notebook13anditspage73. few small hairs on segments 3–6. Hypopygium
largelybrown,withapalebrownanaltube,andas
Fig.1c–d.Legswithbrowncoxaetotibiaeonthe
4.Megaseliaexcorticatasp.n. middle and hind legs, with mainly pale brown
(Fig.1a–d) coxaetofemoraonfrontlegsandthereststraw
yellow.Foretarsuswithposterodorsalhairpali-
This species closely resembles Megaselia igno- sade on segments 1–4 and 4 and 5 subequal in
bilis (Schmitz) (see below), which has been re- length.Theslightlyanterodorsalhairpalisadeof
ENTOMOL.FENNICAVol.20 (cid:127) ScuttlefliesfromFinlandandN.W.Russia 259
Fig2.Megaseliaigno-
bilis.–a.Male,leftface
ofhypopygium.–b.
Rightfaceofhypopygi-
um.–c.Male,right
palpfromabove.–d.
Female,fronswithbris-
tlesrepresentedby
theirbasalsocketsonly.
–e.Female,abdominal
tergites5–7.Scalebars
=0.1mm.
midtibiaextendsjustovertwofifthsofitslength. andhairedasmale.T5–T7asFig.1.Ventergrey
Hairs below basal half of hind femur a little and with hairs below segments 3–6 as in male.
shorter than those of anteroventral row of outer Sternite 7 absent. Posterolateral lobes at rear of
half. Hind tibia with 15–16 differentiated sternum8truncatedandwith3longerhairsatrear
posterodorsalhairsandspinulesofapicalcombs margin and 4–6 shorter hairs in front of these.
simple. Wings 1.2 mm long. Costal index 0.40. Cerci whitish grey and about twice as long as
Costalratios3.90:0.92:1.Costalcilia(ofsection wide. Neither the rectal papillae, the furca, nor
3)0.07–0.08mmlong.Nohairatbaseofvein3. Dufour’s crop mechanismevident. Legs similar
Withtwoaxillarybristles,theouterbeingalittle to male. Wing as male except length is 1.2–1.3
longerthancostalcilia.ScnotreachingR1.All mm. Costal index as little as 0.36. Costal ratios
veins grey, but 7 very pale. Membrane only 3.5–5.6:0.8–1.8:1.Otherwiseitandhaltereas
lightlytingedgrey.Halterebrown. male.
Female.Fronssimilartomalebutwithupto Materialexamined.Holotypemale,Finland,
50 hairs. Labrum 0.7x as wide as diameter of Sotkamo, Hiidenportti National Park, grid ref.
postpedicel. Otherwise head similar to male. 7090405:3601477,exaspenlog(base),17.VIII.
Thoraxasmale,butwith2–4(mostwith3)hairs 2006(276,CUMZ:13–75).Paratypes:1female
on mesopleuron. Abdominal tergites coloured asholotype;1male,3femalesasholotypeexcept
260 Disney (cid:127) ENTOMOL.FENNICAVol.20
Fig.3.Megaselialimburgensismale,leftfaceofhypo-
pygiumtiltedalittledorsally.Scalebar=0.1mm.
Fig.4.Megaselialimburgensismale,posteriorfaces
grid ref. 7088702: 3603800, 31.VII.2004, 7. & ofthebasesofthehindfemoraoftwodifferentspeci-
14.VIII.2006(298,298A,CUMZ,13–73&77); mens.Scalebars=0.1mm.
1 female, Puolanka, Paljakka Strict Nature Re-
serve, grid ref. 7182240:3550701, ex aspen log
(mid),2.–9.IX.2004(373,CUMZ:13–76);1fe- labella. The female of M. fenestralis has longer
male,Puolanka,PaljakkaStrictNatureReserve, darkercerciandabrownlabrum.
grid ref. 7181573:3550145, ex silver birch log
(canopy),29.VI.2005(385,CUMZ:13–76).
Etymology.Thenamereferstothespeciesbe- 5.Megaselialimburgensis
ingrearedfromthebarkoflogs. (Schmitz,1918)(Figs3,4)
Affinities.InthekeystothemalesoftheBrit-
ishspecies(Disney1989)themalerunstocou- AphiochaetalimburgensisSchmitz,1918:57.
plet130, to M. ignobilis(Schmitz), however its This species was described without any fig-
hypopygiumdiffers(cf.Figs.1c–dand2a–b)and ures of critical features and its recognition has
palpisalittlesmaller(cf.Figs.1band2c). since caused problems. Thus Robinson (1981)
InthekeysofSchmitz&Delage(1974)the mistakenly synonymised it with M. fungivora
malerunstocouplet14onpage639,wheretaking (Wood)onthebasisoftheNearcticspecimensat-
either lead proceeds to species with different tributedtoM.limburgensisbyBorgmeier(1964).
hypopygia.Ifsomemalespossessacostalindex However,Borgmeierhadmisidentifiedhisspeci-
andratiossimilartosomeofthefemalesthenit mens. The specimen from Finland is somewhat
wouldrunouttoM.divergens(Malloch)atcou- larger,withawinglengthof2.1mm,thanasindi-
plet6(onpage638).This,however,isamisiden- cated by Schmitz (1957), who gave the wing
tificationforM.fenestralis(Schmitz)whichwas length as 1.75 mm. However, the hypopygium
subsequently rescued from synonymy with (Fig.3)matchesthatofsmallerspecimens.
Malloch’s Nearctic species (Disney 1987). M. Materialexamined.Finland:1male,Kuhmo,
fenestralismaleshavethickerforetarsi(likeM. Juortanansalo-Lapinsuo Mire Reserve, grid ref.
divergens),withsegment5distinctlylongerthan 7166566:637974,exsprucelog(canopy),20VI
4, and a different hypopygium (e.g. with dis- 2006(237,CUMZ:13–74).
tinctlylongerhairsatthetipoftheproctiger). Natural history. This species has been re-
The female closely resembles that of M. ported from the leaf mine of the agromyzid
ignobilis, but differs in the shape of abdominal Phytomyza soenderupi on Caltha palustris
tergites5–7(cfFigs.1aand2e)andthenarrower (Ranunculaceae) (Hering 1951) and Schmitz
ENTOMOL.FENNICAVol.20 (cid:127) ScuttlefliesfromFinlandandN.W.Russia 261
Fig.5.Megaseliamiki
male.–a.Rightpalp.
–b.Leftnotopleuron.
–c.Rightfaceofepan-
driumandhypandrium.
–d.Leftfaceofhypo-
pygium.Scalebar=0.1
mm.
(1957) reported it reared from the frass of Natural history. The larvae prey upon the
curculionidandscolytidbeetles. eggs of spiders (probably Enoplognatha or Ro-
bertus, Theridiidae), Argiope sp. (Araneidae),
pluseggsacsofunknownspiders,therebeing1–
6.Megaselialongifurca
20(mean5.0)adultfliesrearedpersac.Recorded
(Lundbeck,1921)
infestation rates were 11.6–20.0%. A rearing
AphiochaetalingifurcaLundbeck,1921:141. fromanunidentifiedagaricsporophorepossibly
Therecognitionofthisspecieswasclarified originated from an overlooked spider egg sac
byDisney(1999). concealedbetweenthegillsofthefungus(Disney
Materialexamined.Finland:1male,Kuhmo, 1994,1999).Adultsrepresentedupto4.7%ofthe
Ulvinsalo Strict Nature Reserve, grid ref. Phoridaeobtainedfromthecanopiesofoaktrees
7098950:36629493,exaspenlog(base),20.–26. (Quercus spp.) in woods near Oxford (1980 –
VII.2005 (3); 1 female, same locality, grid ref. 1984),usingtheinsecticideknockdownmethod
7099418 3663224, ex spruce log (mid), 13–19. (Disney1994,1999).
VII.2005 (45). 1 male, Kuhmo, Elimyssalo Na-
ture Reserve, grid ref. 7126522:3660575, ex
spruce log (base), 3.–9.VIII.2005 (105); 1 fe- 7.MegaseliamikiSchmitz,1929
male,samelocality,gridref.71265723660480, (Fig.5a–d)
exsprucelog(base),13.–19.VII.2005(106);1fe-
male,samelocality,gridref.7125195:3661592, MegaseliamikiSchmitz,1929:127.
ex pine log (base), 13.–19.VII.2005 (145). 2 Thisspecieswasdescribedfrommalesonly
males,Sotkamo,HiidenporttiNationalPark,grid andwithoutanyfigures,butIhavepreviouslyex-
ref.7090832:3601382263,expinelog(base),3 amined two paratypes in the Museum Koenig
VII2006(263).1male,Russia:StateForestryof (Bonn)whichallowsmetoconfirmtheidentifi-
Kostomuksha (Kostamus) District, grid ref. cation.Themalereadilyrunstocouplet270inthe
7168990:3657471, ex silver birch log (upper), key to the males of the British species of
10.VII.2006(467). Megaselia(Disney1989)andthenrunsintodiffi-
262 Disney (cid:127) ENTOMOL.FENNICAVol.20
cultiesbeyondthispoint.However,ithasadis-
tinctivehypopygium(Fig.5c,d),afinenotopleu-
ral cleft in front of the two bristles on the
notopleuron(Fig.5b),aconspicuoussensorypit
onthepalp(Fig.5a)andatleasttwodozensubcu-
taneouspitsensillainthepostpedicel.
Materialexamined.Finland,1male,Kuhmo,
Juortanansalo-Lapinsuo Mire Reserve, grid ref.
7167884 3642689, ex pine log (base), 20.–
26.VII.2005(186,CUMZ:13–73).
8.MegaseliarobertsoniDisney,2008
MegaseliarobertsoniDisney,2008:65.
Thisspecieswasdescribedfromasinglemale
reared from a pupa found under the bark of a
sprucestumpinNorway.
Fig.6.Megaseliasetulipalpismale.–a.Leftfaceof
Material examined. 1 male, Finland, Sotka- hypopygium(tiledalittletowardsviewer).–b).Poste-
mo,HiidenporttiNationalPark,gridref.7088702 riorfaceofbaseofhindfemur.Scalebar=0.1mm.
3603800, ex aspen log (base), 31.VII.2004
(298A,CUMZ:13–77).
7126008:3660548, spruce (branch), 3.VII.2006
9.MegaseliasetulipalpisSchmitz,1938 (124);1female,Kuhmo,Juortanansalo-Lapinsuo
(Figs.6a–b,7a–d) MireReserve,gridref.7167560:3643110193,ex
silverbirch(branch),26.VI–5.VII.2005(193).
MegaseliasetulipalpisSchmitz,1938:187. Other material examined: Holotype male,
I have remounted the holotype male of M. The Netherlands, Valkenburg, 20.VII–10.VIII.
setulipalpis in Euparal. Schmitz (1958, Textfig. 1933, H. Schmitz (ZFMK). 2 males, England,
242)illustratedtheterminalabdominalsegments North Yorkshire, Park End Wood, birch wood
ofthefemale. (Gridref.35/923260),22.–25.VI.1981,R.H.L.
Schmitz (1958) gave the wing length of the Disney(CUMZ,7–100).1male,Germany,Ulm,
maleas1.7mm,thecostalindexas0.48–0.50,the 13.–21.V.1992,M.Buck(VH1TE3,CUMZ,26–
costalratiosas2.9–3.7:1.5–1.9:1andthelength 0). 1 male, Poland, Forest of Bialowieska,
of the costal cilia as 0.08–0.09 mm. For males 27.VIII.1987,E.Durska(667Bf,CUMZ,8–74).
fromBritain,thewinglengthsrangefrom1.3–1.8 2males,1female,Scotland,Aviemore,byRiver
mm,thecostalindexrangesfrom0.47–0.50and Spey(Gridref.28/893112),aldercarr,9.–13.VII.
theratiosandcostalcilialengthscoverthesame 1982, R. H. L. Disney (CUMZ, 8–29); 1 male,
ranges,butaspecimenfromPolandhasthecostal CraigellachieNationalNatureReserve(Gridref.
ratiosas4.5:2.5:1andthecostalciliaas0.10 28/891116), 13.VII.1982, R. H. L. Disney
mmlong.ForthefemaleSchmitzgavetheCIas (CUMZ,8–41).
0.50andthecostalratiosas3.1:1.5–1.6:1.For Naturalhistory.Adultshavepreviouslybeen
thetwofemalesbelowtherangesare1.9–2.1mm reportedemerginginnumbersfromthetrunkofa
forthewinglength,0.49–0.50forthecostalin- dead spruce (Prescher& Wermelinger, unpub-
dex,3.4–3.7:1.6–1.9:1forthecostalratios,and lished;citedbyWeberetal.2007).However,Dr
0.09–0.10forthelengthofthecostalcilia. Sabine Prescher kindly confirmed that this spe-
Materialexamined:1female,Finland,Kuh- cieswasthatdescribedbelowandsentmeamale
mo, Elimyssalo Nature Reserve, grid ref. andfemalefromthisseries(seebelow)
ENTOMOL.FENNICAVol.20 (cid:127) ScuttlefliesfromFinlandandN.W.Russia 263
Fig.7.Megaselia
setulipalpis.–a.Male,
leftfaceofhypopygi-
um.–b.Female,right
labellumandglossa
frombelow.–c.Male,
fronswithbristlesrep-
resentedbytheirbasal
socketsonly(al=
anterolatral,a=antial,
usa=uppersupra-
antennal).–d.Fe-
male,abdominalter-
gites5–7.Scalebars
=0.1mm.
10.Megaseliatignorumsp.n. 0.4x as broad as postpedicel but longer than
(Fig.8a–d) breadth of latter, with three longer and three
shorterbristlesand3–7hairs.Labrumpalestraw
This species closely resembles M. setulipalpis yellowandatmost0.6xaswideaspostpedicel.
(seebelow). Labellapaleyellow,butpartlypalebrownontop,
Male.Fronsbrown,clearlybroaderthanlong, andwithnumerousshortspinulesbelownotob-
with 52–62 hairs and dense but very fine viously arranged in rows. Thorax brown. Three
microsetae.Bristlesarrangementonfronssimilar notopleuralbristlesandnocleftinfrontofthese.
to Fig. 7c, but the upper SAs tend to be a little Mesopleuronwith8–17hairsand1–2differenti-
higheronthefronsthantheantialsandthelatter atedbristlesatrearmargin.Scutellumwithanan-
tendtobealittleclosertotheALsthantotheSAs. teriorpairofhairs(shorterthanthoseinmiddleof
Cheekwith2–4bristlesandjowlwith2–4longer scutum)andaposteriorpairofbristles.Abdomi-
ones.Postpedicelsbrown,subgloboseandwith- naltergitesbrownwithhairsatrearmarginslon-
outSPSvesicles.Palpsduskystrawyellow,about gerthanrestandthoseatrearofT6thelongest.
264 Disney (cid:127) ENTOMOL.FENNICAVol.20
Fig.8.Megaseliatigno-
rum.–a.Male,rightface
ofhypopygium.–b.Left
faceofhypopygium.–c.
Female,abdominalter-
gites4–7.–d.Female,
lobesatrearofabdomi-
nalsternum8.Scale
bars=0.1mm.
Venter brown, and with hairs on segments 3–6. about 0.7x as wide the diameter of postpedicel.
Hypopygiumbrown,withapalebrownanaltube Thoraxasmale,therebeing9–11hairsplusthe
andstrawyellowleftlobeofthehypandrium,and bristle on the mesopleuron. Abdominal tergites
asFig.8aand8b.Midandhindlegswithbrown brown.T4–T7asFig.8c.Venterbrownishgrey,
coxaetotibiaeanddirtyyellowtarsi.Frontlegs and with hairs below segments 3–6. Sternite 7
withcoxaeandfemorapartbrownandpartstraw representedbyhairsonly.Posterolaterallobesat
yellow and rest dusky yellow. Fore tarsus with rearofsternum8asFig.8d.Cercipalebutlightly
posterodorsalhairpalisadeonsegments1–5and tinged brown and abouttwiceas long as broad.
5aboutaslongas4.Dorsalhairpalisadeofmid With four rectal papillae. Furca not evident.
tibiaextendstwofifthstohalfitslength.Hairsbe- Dufour’scropmechanismbilobedbehind.Legs
low basal half of hind femur about as long as similartomalebuthairsbelowbasalhalfofhind
those of anteroventral row of outer half. Hind femurareshorterthanthoseofanteroventralrow
tibiawithadozenormoredifferentiatedpostero- indistalhalf.Wingasmale,withwinglength1.3–
dorsalhairsandspinulesofapicalcombssimple. 1.4mm,costalindex0.45–0.46,costalratios3.6–
Wings1.3–1.6mmlong.Costalindex0.45–0.47. 3.9 : 1.6–1.8 : 1 and costal cilia 0.07–0.08 mm
Costalratios3.4–4.6:1.5–1.8:1.Costalcilia(of long.Otherwiseitandhaltereasmale.
section 3) 0.07–0.09 mm long. A small hair at Materialexamined.Holotypemale,Finland,
baseofvein3presentorabsent,whenpresentitis Kuhmo, Ulvinsalo Strict Nature Reserve, grid
assmallasthefirsthairsatbaseofcosta.With3 ref.7099758:3662603,exsprucelog(mid),22–
axillarybristles,theoutertwobeinglongerthan 28.VI.2005(19);1male,Kuhmo,Juortanansalo-
costal cilia. Sc not reaching R1. All veins light Lapinsuo Mire Reserve, grid ref. 7168158:
grey.Membranelightlytingedgrey(justevident 3642387, spruce log (base), 20.–26.VII.2005
tonakedeyewhenviewedagainstawhiteback- (180); 1 male, same locality, grid ref. 7166566:
ground).Halterebrown. 3637974, ex spruce log (mid), 3.–9.VIII.2005
Female.Headsimilartomalebutthelabrum (237); 1 male, Puolanka, Paljakka Strict Nature
ENTOMOL.FENNICAVol.20 (cid:127) ScuttlefliesfromFinlandandN.W.Russia 265
Reserve, grid ref. 7183767 3550404, pine log 11.Megaseliaspecies
(mid),20.–26.VII.2005,(358);1female,Finland, notdeterminedA
Puolanka, Paljakka Strict Nature Reserve, grid
ref.7180449:3550938,exsprucelog(base),20– This species resembles the female of M. tigno-
24.VII.2005(390,CUMZ,13–72);1male,same rum,butitislarger(winglengthabout1.9,asop-
locality, spruce log (mid), 12.VII.–2.VIII.2005 posed to <1.5 mm), with a longer costal index
(362). 1 male, England, North Yorkshire, Mal- (0.50asopposedto0.45–0.46)andlongercostal
hamTarnNationalNatureReserve,Northedgeof cilia(0.11–0.12asopposedto0.08mm).Itispos-
EastFen(Gridref.34/889672),pitfalltrap,28.– sibly thehithertounknownfemaleofM. insons
29.VI.1984 (CUMZ, 14–18). 1 male, 1 female, (Lundbeck)(seebelow).
Switzerland, Sernftal, ex spruce trunk, 17.V. & Female. Frons brown, clearly broader than
30.VIII.1995, B. Wermelinger (leg. Dr Sabine long, with 52–54 hairs and dense but very fine
Prescher)(CUMZ,13–77). microsetae. SAs unequal, the lower pair being
Etymology. The name refers to procurement shorter and weaker. The antials very slightly
fromlogs. lower on frons than upper SAs but the
Affinities.InthekeystothemalesoftheBrit- anterolateralsslightlyhigher,andclosertolatter
ishspecies(Disney1989)themalerunstocou- thantoupperSAs.Pre-ocellarsalittlecloserto-
plet 59, where it runs to M. setulipalpis but the getherthaneitherisfromamediolateralbristle,
hairsbelowthebasalhalfofthehindfemurare and all four bristles in an almost straight line.
fewer and not so robust. Anote suggests that if Cheekwithfourbristlesandjowlwithtwolonger
neither lead applies one should try couplet 92, ones. The subglobose postpedicels dark brown,
from where one then proceeds to couplet 98, without SPS vesicles. Palps straw yellow, with
whereclearlyneitherleadapplies.Inthekeysof five strong bristles, one weaker one and half a
Schmitz (1957) the male runs to couplet 21, on dozenhairs.Labrumcolouredaspalpsandabout
page432,toM.setulipalpis. threequartersthewidthofapostpedicel.Labella
Both the male and female are distinguished palerandwithupto50shortspinulesbeloweach.
fromM.setulipalpisbyhavingthespinulesonthe Thoraxbrown.Threenotopleuralbristlesandno
lowerfaceofthelabellabeingnotrestrictedtoa cleftinfrontofthese.Mesopleuronwith8small
narrow band on each. Those of the male of M. hairsandononesideonlywithashortdifferenti-
setulipalpisarein6–7irregularrowsbutthereare ated bristle as well. Scutellum with an anterior
fewer rows in the female (Fig. 7b). In the new pair of hairs (about equal to those in middle of
speciestheyarenotcrowdedintosuchrowsbut scutum)andaposteriorpairofbristles.Abdomi-
aremoregenerallydispersed.Theposterolateral naltergitesbrown,withthehairsatrearofT6and
marginsoftherightsideoftheepandriumdiffer, T7 distinctly longer than the rest. T8 is clearly
withthatofM.setulipalpisslopingforwards,as longer thaninM. setulipalpisandM. tignorum,
opposedtobeingdirectedmoreventrally(cfFig. beingabout0.15mmlongandthusalmostaslong
7awithFig.8aand8b).Thefemalesarefurther as T7 (which is about 0.16 mm long). Venter
distinguished by their abdominal tergites 6 (cf brown, and with hairs below segments 3–6.
Figs.7dand8c).InthisitsT6resemblesthatof Sternite 7 about 0.10 mm long. Posterolateral
M.armata(Wood).However,thepairedlobesat lobesatrearofsternum8veryshortbutwith3–4
therearofabdominalsternum8ofWood’sspe- stronghairsatrearmargin.Cercilightbrownand
cieslackthepalebarepointsofthenewspecies about 2.2x as long as broad. With four rectal
(Fig.8d).Inbothsexesthecostalindexisalittle papillae. Dufour’s crop mechanism about 0.34
lessthaninM.setulipalpis. mm long and bilobed behind. Legs with brown
Naturalhistory.ThetwoparatypesfromSwit- mid and hind femora, part straw yellow part
zerlandwerefromtheseriespreviouslyreported brownmidandhindtibiae,andtherestmainlya
emerging in numbers from the trunk of a dead dusky straw yellow apart from brown patch on
spruce(citedby Weber etal.2007),thespecies midcoxa.Foretarsuswithposterodorsalhairpal-
beingreferredtoasM.setulipalpis. isade on segments 1–5 and 5 not longer than 4.
Dorsal hair palisade of mid tibia extends about
266 Disney (cid:127) ENTOMOL.FENNICAVol.20
twothirdsofitslength.Hairsbelowbasalhalfof encetothetexttocircumventcoupletsbasedon
hindfemur,beingaboutasstrongasthoseonthe themalesexonly,tocouplet18,toM.setulipalpis
anterior face, are clearly shorter than those of (from which it is distinguished in the previous
anteroventral row of outer half. Hind tibia with paragraph).However,thecostalciliaonsection1
17–18differentiatedposterodorsalhairsandspi- are longer and so this species could equally be
nulesofapicalcombssimple.Wings1.6–1.9mm taken through the keys of Schmitz & Beyer
long.Costalindex0.49–0.50.Costalratios3.2– (1965)toAbteilungIV,ZweiteReihe.However,
3.5:1.7–1.8:1.Costalcilia(ofsection3)0.11– thiskeyreliesheavilyonmalefeaturesand,even
0.12mmlong.Hairatbaseofvein3verysmall, withfrequentreferencetothetextforinformation
being shorter than width of vein. With four onfemales,isnoteasytousewithconfidence.It
axillary bristles, all being shorter than longest seemsmostreadilytorunouttocouplets83to97
costalcilia.ScnotreachingR1.Thickveinsgrey- but cannot be assigned with confidence to any
ish yellow, thin veins grey. Membrane lightly speciesinthissection.
tinged grey (just evident to naked eye when It is most probable that this specimen is the
viewed against a white background). Haltere hithertounknownfemaleofM.insons,butuntil
brown. associatedwiththemalethisremainsonlyatenta-
Materialexamined.1female,Finland:Sotka- tivehypothesisrequiringtesting.
mo, Hiidenportti National Park, grid ref.
7088702:3603800, ex aspen log, 31.VII.2004
(298A, CUMZ: 13–77); 1 female, Puolanka,
12.Megaseliaspecies
Paljakka Strict Nature Reserve, grid ref.
notdeterminedB
7182440:3550688,exaspenlog(base),14.VIII.
2006(377,CUMZ,13–76).
Affinities. In the keys of Schmitz (1957), if Thesinglemaleisprobablyanundescribedspe-
thisspeciesisregardedashavingadifferentiated cies,howeverthespecimenissomewhatteneral
bristle at the rear margin of the mesopleuron, it and is not being fully described until a better
willruntocouplet17onpage432.Ifthecostal specimenisavailable.InthekeystoBritishspe-
cilia are treated as short it will run on to M. cies(Disney1989)itrunstocouplet126,butthe
setulipalpis,fromwhichthescatteredspinulesof hypopygiumwilldistinguishitfromthetwospe-
theventralfacesofthelabellawillimmediately ciesofthiscouplet.Ofthenon-BritishEuropean
distinguishit.Thelongercostalindexwilldistin- species that run to the same couplet M. aristica
guishitfromM.tignorum(above).Ifatcouplet (Schmitz)andM.digitalisSchmitznotonlyhave
17onetakesthesecondleadoneproceedstocou- different hypopygia but their anterolateral bris-
plet30.Ofthefivespeciescoveredbytheremain- tlesonthefronsarealmostlevelwiththeantials,
ingthreecoupletsthreehavebeensynonymised butinspeciesBtheALsareclearlyhigheronthe
withM.frameataSchmitz,leavingonlyitandM. frons.ThespeciesM.jameslamontiDisneyhasa
insons (Lundbeck), whose female is unknown. much longer anal tube than species B. The key
However, two further species of this complex detailsofthewingarewinglength1.0mm;costal
havebeendescribedsince(Disney2006,2008). index0.36–0.37;costalratios3.9:1.1:1;costal
The bilobed dufour’s crop mechanism immedi- cilia 0.06 mm long; and the haltere is brown.
ately distinguishes it from M. frameata and M. These features allow it to run to couplet 13 on
shawi.ThefemaleofM.robertsoni(2008)isun- page639ofthekeyofSchmitz&Delage(1974).
known, but its male is smaller (wing length 1.3 However,thiscoupletreferstothefemalesonly
mm),itscostalindexshorter(0.46)andlikewise oftwospecieswhosemalesruntocouplet9,and
itscostalcilia(0.07mm). which are distinguished by their distinctive
Ifthisspeciesisregardedashavinghairsonly hypopygia.
on the mesopleuron, and with the costal cilia Materialexamined:1male,Russia:StateFor-
<0.10 mm long (or at most <0.125 mm), in the estry ofKostomuksha(Kostamus) District, grid
keys of Schmitz (1958) to Abteilung IV, Erste ref.7169259:3657699,exsilverbirchlog,6.IX.
Reiheitwillrun,withsomedifficultyandrefer- 2005(470A,CUMZ,13–78).