Annotated Keys to the Genera of the Tribe Diamesini (Diptera: Chironomidae), Descriptions of the Female and Immatures of Potthastia iberica Tosio, and Keys to the Known Species of Potthastia
Item Type Technical Report
Authors Doughman, Jan S.
Publisher University of Alaska, Institute of Water Resources and Engineering Experiment Station
Download date 04/10/2021 13:57:41
Link to Item http://hdl.handle.net/11122/1820 ...... ; ... :.. .; .~ ... : .: '~."~:" ~ ..•.. ; . :.: ':~:;~ ......
(Diptera: Chironomidae), Descriptions of the Female and Immatures of Potthastia iberica Tosio, and Keys to the Known Species of Potthastia
Jan S. Doughman I U.S. Geological Survey ] i I I r I I! . Institute of Water Resources/Engineering Experiment Station University of Alaska-Fairbanks Fairbanks. Alaska 99775
Report IWR-107 August 1985 .·· ABSTRACT
A review of available inCormation on the tribe Diamesini led to the construction oC generic keys to -most liCe stages. Serra-Tosio (1971b) first described Potthastia iberica Crom an adult male from the Spanish Pyrenees. Evaluation of specimens collected in the Nearctic, from Idaho (in 1967) and Georgia (in 1981 and 1983), indicate that this species is extant in eastern and western highland streams that appear to be typ1cal trout streams. This new group of specimens contained a mature male and female pupa and immatures, and associations made it possible to describe the female and the immatures for the first time. Adult specimens conform very closely to the hololype. The known species of Potthastia are keyed.
ii TAllLE OF CONTENTS
Abstract. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • i i
Introduction ••• •.• ••••• • • •• " . • •••• .•••• . • •••• • • •• •••••• •• • •• •
Generic keys to the adult males, pupae and larvae of the
tribe Diamesini, with /I key to the series oC Potthastia. • • • • • • • • • • • • • • 3
Males • •• . " •.•• • . •• • •• • •• • • •.•• • " • • •• ••••••• " • • • • • • • • 5
Pupae. • . • . • • • • • • . • • • • • • • • . • • . . • • •. • • • • • . • • • • • • • • • • • • • •• 12
Larvae. • • • • • . • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • . • • • • . 14
Pottthastia Iberica Serra-Tosio. • • • • • • • . • • • • • • • • • • • • • • • • • • • • . • • • • • 20
Female • •••• • • .• •• • •• • • ••••. • • • ••• " • . • • . • • • •• • •• • • • • • • 21
Pupa. • • • • • • • • • • • • • • • • • • • • • • • . • • • • • • • • • • • • • • • .. • • • • •• • 21
Larva. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • . • • • • • • • • • • • • • • • • 24
Material. • • • • • . • • • • • • • • • • • • • • . • • • • • • • • •• • • • . • • • • . • • • • •. • 26
Ecology ••• •• • •• • • • ••••• • ••••..• •• • • " • ••• • •• • " • • • • • • •• 26
Acknowledgements. . • • . . • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 28
References • • • • " • • • • • • • . • • • • • • • • • • • • . • • • • • • • • • • • • • • • • • • • . • • • 29
Captions. • . • • • • • • • . • • • • • • • • . • • . • • • . • • • • • • • • • • • • • • • • • • • • • • • • • 35
Figures. . • • • • • • • • • . • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • . • • • • • • • • •• 38
iii INTRODUCTION
Pagast (1947) published Il compendium of prior descriptions of species milking
up the tribe Piamesini. This work summarized the previous findings oC such workers
as Goetghebuer,KieHer, Edwards, and Thienemann on adults and pupae. Johannsen
(1937), Thienemann (1952), Roback (1957) and Pankrlltovll (1970) produced keys to the
larvae of this tribe. The descriptions provided in these works are insufficient t() Cully
·differentillte the genera and species as presently conceived. More recent works by
Oliver (1959), Serra-Tosio (1971a), Hansen and Cook (1976), Rossaro (1980a, b), and
Kownacki (1981) include more complete descriptions or clarify some of the taxonomic
problems that Pagast (1947) did not consider. Doughman (1983) has keyed and
described the known .larvae a·nd summarized data on the distribution and
nomenclature of four genera of the subfamily Diamesinae sensu Sa ether.
The phylogeny of the tribe Diamesini has been established through the works of
Pagast (1947) Brundin (1966), and Saether (1976, 1977, 1979). Serra-Tosio (1968)
prepared a different phylogenetic scheme which was essentially an inversion of the
prior schemata. Saewedal (1982)andWi1!assen (1982) questioned thecorreclness of
Serra-Tosio's revisions.
This tribe has some heterogeneous genera showing a wide variety in hypopygial
structures (e.g., Diamesa and Syndiamesa). The genera Potthastia lind PagasUa were
erected on relatively abnormal species as reClectedby the larval stage (Pagast, 1947,
Oliver, 1959). Q. appendiculata Lundstroem does not faU neatly into any known
genus. Onychodiamesa P.agast and Lappodiamesa Serra-Tosio were erected only Crom
the adult. Taxonomic placement problems as those associated with Hesperodiamesa
(Sublette, 1967a) could be avoided if the erection of new genera in the tribe
Diamesini were delayed until other life stages are known. Therefore, it cll,n be
assumed that the intrinsic relationships of the Diamesini are not yet settled. Through the framework of the key, modern descriptions of the genera in the
Ildult male, pupal, and larval states are summarized from many .foreign papers in this
report. In like manner, a summary of Potthastia is specifically addressed. The
immatu.res of ~. iberica Serra-Tosio described herein revealed that Potthastia gaedii
Meigen has n unique group of characteristics in nil stages. This paper is directed to
the applied worker in water-quality stUdies. Hopefully, this translation/summary is sufficient, necessitating one to secure only the more recent treatments of these
genera at the species level.
2 GENERIC KEYS TO THE ADULT MALES, PUPAE AND LARVAE OF THE TRIBE DIAMESINI,
WITH A KEy TO THE SPI!CIES OF POTTHASTlA
The following remarks pertain directly to the usa of the subsequent keys.
Hesperodiamesll is absorbed into Pagastill (cf. Serra-Tosio, 1976); see Oliver and
Roussel (1982). The species of the genera Syndiamesa (=Parapotthastia Tos.),
Lnppodiamesa, Onychodiamesa, and the Diamesa dampfi-group lire as yet known only
from the Pa1aearctic.
The eye of the imago clln be hairy or not hairy sensu Hansen and Cook (l9lS);
that is, visible trichia between the lenses (ommatidia) surpass the height of these
lenses in the hairy eyed but do not elCceed this height when the term not hairy is used.
Furthermore, the term naked means that no obvious trichia at x400 can be seen
between the lenses of the eye. The use of the term inferior voseUa (IVo) (Saether
1980; fig. 16) means any differential media) bulge or protrusion(s) of thegonocoKite
that originates proximally, that has its distal end somewhat free or obviously
pendulous, ·and that possesses on the distal portion at least, medium long,
perpendicular setae. The aedeagus sensu Saether (19BO) and Hansen and Cook (1976),
or the dorsal piece sensu Serra-Tosio (lg7la) is termed superior volsella. A secondary
·branch, the "penis", is termed the median volsella. It is noticeable only in the sister
genera Potthastia and Sympotthastia. Leg (fore, mid, and hind), venarum, and ratios
of palp. length (segments 2-5) to fa~ial width arc eKpressed as percent. Many
descriptors arc taken from Serra-Tosio {196B, 1970, 1971a, 1976). The reader is
referred to Serra-Tosio (1968 or 1971a) and Hansen and Cook (1976) for their
exccllent hypogygial drawings.
The pupal key uses Pngast (1947) and Ferrarese and Rossaro (19B1), and many
pupal descriptions can be found in Serra-Tosio (1971a). Usually male exuviae are
keyed. Female pupae ar·e generally a little larger, with anal lobe more square, and
3 with genital suas squarish and not extending to caudal margin. All diagnostic features nre expeated to be the same as in the mille. The pupa, Q. sp • .I (Pagast,
1947), is apPllrently Q.geminllta Kief. not Q. aependiaulata Lundst. The laconic descriptions of the male, pupa, and lllrva of Q. nppendiculala by Makarchenko (1978) prevent one from discerning its generic status. Its pupa Ilpparently ralls between the two major groups se.parated in couplet 1, .i.e., near Sympotthastia but with some charllcters of PseudokierCeriella. Makarchenko (personal comm.) has recently submitted a paper that will elevate this unique species to a new genus, Arctodiamesa.
Not inclUded in the larval key because of incomplete descriptions are two species in Pankratova (1970). Q. carpatica Botn.et C.-Cure, similar to that found in
Roback (1957) as Q. near fl1lva, is suspected to be near f.gaedii; Q. heterodentata
Botn. et C.-Cure appears to be an undescribed species of Sympotthastia.
Diagnoses used to separate the Diamesini at ·each life state from the other tribes of Chironom idae are placed in preface to each ·of the generic keys. The utilitarian part of each key couplet occurs first with supplemental descr·iptive information following in parentheses. This extra descriptive shOUld not be needed to key a specimen. It was included to provide a rather complete generic description obtainable by back-keying and to contnin all descriptive within easy reach to minimize identification errors.
Figures by the author were traced mostly Crom photomicrographs, or they were drawn using an ocular grid. Care was taken to ensure tha t the relative form, size and placement of structures were correct. However, the pupal shagreen has been some- what schematized. The keys use the terminology of Saether (1980). Unspecified lengths afe in micrometers. Coloration is that Observed on slide mounts. Gray fades tn ·brown, for example, on specimens in a slide preparation.
4 MALES
Adult males of the tribe have the following key characters. Wing: MCu occurring at or slight distal to the Cu Cork; R2+3 simple; Rl and R4+5 in close proximity; Rand RI with setae (eg. fig. 4); membrane with only ultra*fine microtrichia (hyaline), or with largerc!early defined points or trichia, and/or punctate at X400. Dorsocentra! setae not converging posteriorly; scutal setae generally confined to discrete setal patches or lines in a contrastingly lighter field/sockets and dorsolateral surface of scutum not rugose (cf. Oliver, 1981).
Gonocoxite rather simple, tubular and not protruding beyond the articulation of the usually simple gonostyle. Hindtibial comb a row of simple, spiniform, longish spines; tibial spurs thick and possessing secondary spinulae. Body eolorlltion rather uni.form and daric (browns, grays, blacks). Antenna, exc·ept in some Di.amesa, 13 plumose f1nge!lomeres.
1. Antepronotum deeply notched ·(com missure not fused beneath scutal proc·ess as
seen in dorsal view) and possessing lateral or both lateral and medial setae (fig. 3, inset). (Eye naked (no hairs visible between lenses except in f. seguax) and strongly produced dorsomediaUy around antenna. Inner vertical setae (IV) numerous.
Clypeus with numerous setae, mostly covering it. Palp with well*5eparated
segments and equal or somewhat longer ·than width of face at eyes. Acrostichals (Ac) running in single line through mesonotum (nbsent in Ps.
nivosal. Anal lobe of wing very produced, rounded; wing hyaline with
microtrichill visible at X400: R, Rl, R4+5 nnd sometimes wing membrane at tip with setae. Tergite IX (TIX) with numerous setae lateral to anal point (AnP).
AnP long, supported by oblique (terga)) bands, par.ll:llel Sided, usually somewhat
bulbous at tip, and some species possess a terminal spine. Gonocoxi teexpanded
medially at base (L*5haped), stocky, parallel sided. Gonostylus rather brolld in dorsa:! view and apically sunken. bowl-like and strong setae along inner wall of
bowl (fig. 6). Fourth tarsomere (ta4) cylindrical. Coloration very dark; wing veins Bnd haltere colored.)••••••.••••••.•••.•.••.•• , ••••.••.•
Antepronotum not deeply notched a.nd possessing only a group of lateral setae.
3
2. Antepronotum without medial setae. Orbital setae (Or) absent. Dorsocentrals
(Dc) with 2 to 5 rows rearward. Isolated prealars running forward of main
cluster in a double row. IVo only a basal swelling. Superior volsella (SVo) bar
like, not expanded (fig. 51); peg of gonostylus slender or absent (fig. 41). AR
high but variable (2-4). Venarum ratio (Vlil 72-82. Large, wing 5-6 mm.
Pseudodiamesa
Antepronotum with medial setae. Orbital selae present. Dc in one or two,
sometimes three, rows r·earward. Isolated prealars running forward in a single
row. IVo rather bilobed. SVo similar to Diamesa, expanded and triangular. Peg
of gonostylus short, robust. Ta4 much longer than taS" Medium sized, wing 3-4
mm.
(Two groups: (1) antepronotum covered with setae; AR 2.7; VR 84; AnP with
triangular, articulating spine. Ilnd (2) thoracic setal number reduced; AR 1.4-2.0,
VR 92, AnP without articUlllting spine.) .•••. • •.•••••••.••••••..
Pagastia
3. Eye with trichia between the lenses. Orbital setae always present. Eye may be
produced somewhat dorso·medially. SVo naked and usually triangular, (fig. 49);
median volsella (MVo) absent.
(Wing generally with microtrichia as minute dots or visible trichia at X400;
R4 +5 with setae; MCu oCten very close to Cu fork; anal lobe only slightly
produced but usually angulllle.) • • • • • • • • • • • . . • • • . • • . • . • • • • • . .. • •. "
Eye entirely naked between lenses and usually produ.ced dorsomedially. 'SVo 6 variable, but not triangular; MVo setigerous or reduced.
(Wing microtrichia not visible at X400 but may show punctations. Ta4
cylindrical. Gonostylus boat-shaped, ending with a strong right-angled peg and
two noticeable, proximal se-tae forming a straight line with the peg (fig. 1). AnP, when present, small nnd not supported by tergal bands.). • . • • • . • • • 9
4. Ta4 very cordiform and shorter than las. Antenna normal or reduced. Eye hairy or not. Boyd color variable or uniformly dark. (Po uniserial; OV, IV and Or
present. Clypeal setae variable, one to severnl. Palp clearly segmented. Dc
uniseriall. • • . •. •••••.••.•••••••.••••••••• ••••••• •••...•• 5
Ta4 more cylindrical. Antenna normal. Eye not hairy and moderately produced
or rounded dorsomedinlly. Body color uniformly dark. Palp longer than facial
w-idth. •••• • •..• •••.•••.••.••.•••• .•••••. ••.••.•••• .••• 7
5. Eye rounded dorsomedially and hairy or not hairy. Wingmicro-trichia usually
visible at X400 and R4+5 orten with a complete row of setae. Antenna normal
or with reduced plumosity and number of f1agellomeres (to 8). Body often in many shades. (Ac usually completely absent. Prealars confined to single cluster. Anal lobe
of wing acut.e; VR 95:5. AnP usually present, variable and usually supported by
oblique tcrgal bands; pars ventralis (PV-basa.l wedge, sternite X) present;
transverse sternnpodeme variable from simple, thin curve to triangular; SVo
originating from the phallapodeme as a strongly sclerotized, dorsal bar, projecting betwecn gonocoxites, terminally recurved, -and then expanding
Ventrally Bnd proximlllly, forming a transparent triangle as it returns ventraJly
to the phallapodeme. Gonostylus simple (bifid only in Q. geminata) but highly
variable in shape; peg usually present. AR usually less than two.) •
• . • . • • • • • • . • • . • • • • . • • . • • . Dinmesa -(most)
Eye slightly produced. Wing microtrichia not visible a.t X400j wing R4+5 with
7 setae only distally; anill lobe rounded. Antenna normal. Body dark. (Ac absent. Prealars confined to single cluster. AnP needle-like and not
supported by oblique bands. Body and wing 2.5-3.0 mm.) • • • • • • • • • • • • • • 6
6. Gonostylus simple. Eye not hairy. (AR 0.9-1.7. PilIp to face 96. Capitellum white. Wing punctate; VR 86.
LR 69, 47, 59. Hypogygium (fig. 49). Synonyms: Diplomesa lapponica Pag.
and Diamesa tyrolensis Goetg.) • •. PseudokleUeriella parva Edw. GonostyllJs bifidllnd peg large and serrate. Eye hairy. (AR 1.0-1.2. Wing
trllnsparate, milkwhitei capitellum dusky. LR 6 7~76. SVo Qnd virga serrate• •
Arctodiamesa appendiculata Lundst. 7. AnP usually absent or, if present, blunt and pubescent (in dorsal vieW). AR
usually about 2(1.0 to 3.0). Ac present on pronotum or lacking; Dc multiserial;
ptealats often with a few forward, isolated setae•••••••.••••••• , .... 8 AnP present: short, narrow, bare, weak and not supported or robust, nairy,and
robust, hairy, and supported by oblique tergal bands. AR about 1. Ac absent;
Dc uniserial; preillars confined to single cluster.
(IVo sometimes produced to mid-gonocolCite. PV prominent, tongue-like. Gonostylus rather thickened without arista dorsalis, and with only one peg. SVo
double pointed distally with at least the ventral point dark (fig. 52), or ending
mace-like with blunt tubercles and highly sclerotlzed. AnP weak and bare, or
strong and hairy. Eyes rounded. Transverse sternapodene thickened, squarish.
Po, Iv and Or present. Few (5) clypeal setae. '1'9.4 shorter than taS' LR 63. Thorax sometimes weakly showing scutal stripes. Body 4.5 mmj wing 4 mm.) •••
8. Eye rounded. Gonostylus reflex ed, narrow and tubular in lateral view and flared
b6Sally in dorsal view; peg large, barrel-form. GonocolCite swollen medially.
AR high. Ta4 somewhat cordiform and shorter tllan TaS' Body 4.5; wing 4-5
8 mm. Monotypic; cf. PBgast(1947). (cl. §. franzi Goetg.?) ••••••••.
Onychodiame~a
Eye often somewhat produced dorsotnediillly and not hairy. Gonostylus usually thin, refiexed and often with a basal crista dorsalis (fig. 5) or supernumerary
pegs. Gonocoxite linear with only a small, naked or hirsute, base.} IVo (fig. 53).
Ta4 cylindrical and about equal to ta 5' Clypeal setae numerous, dark and robust.
(Two groups (~ Kownacki, 1981): (1) AR about 1; All less than 600 urn
(except §. kashlmae); eye not conspicuously producjed. Ac 0-5; preaiars with 0-2
isolated, forward setae. LR less thlm 67; AnP, if present only a broad,
pub~cimt protrusion be TIXj gonostylus not sickle-shllped but having many
terminal pegs or a crista (except ~. nigra), and (2) AR 2.0-2.5j Al3 greater thim
800 urnj eye produced; Acj usually covering prOnolUmj preaiars with 4 isolated,
forward setae; LR greater than 67; AnP absentj gonostylus narrow and reflexed
and usually with a basal crista and only one peg.).
Syndiamesa
9. At! present. Prealars confined to 11 single cluster. Post orbital setae (Po)
absent at mid-eyej inner verticals (IV) fairly numerous, extending to corona.
(Wing hyaline and slightly punctate with only few setae on R4+5j VR 89-92. Eye
moderately prolonged. Palp to face 17-84. Clypeus with 6-10 setae. Dc uniserlill. AnP near l. giledii. SVo clavatej MVo not describedj IVo not free but extending nearly to end of gonocoxite (fig. 50). LR 68,59,70. AnP 100 urn,
blade-like, naked. AR 1.5; A14 730 urn long. Body brown, 4.5 mmj wing 3.5 mm.
Cf. ;'Q." vidul1 Kief. Monotypic, cf. Serra-Tosio (1968).) • •••
Lappodiamesa Ac absent. Prealars with at least one seta tree and anterior of cluster. Po in
continuous single or multiple row; iV reaching only to top of eye. • • • • • 10 9 10. Dc mostly in a staggered single row (fig. 3). Wing punctations not visible at
X400. Ta4 cordiform and shorter and tas. Palpal segments distinct. Po uniserial. (Capitelluili usUally Illear. A13 cylindriclll apically. VR 94. Eye somewhat t>rodUced or broadly rounded dorsomediilily. Ani', if present, blunt and hairy.) • • • • . • • • • • • • • . • • • • • • " ••• • Potth.astia • • • • • • • • • • • • • • • • • •• 11
Dc in severlll rows. Wing punctiltlons easily discerned at X400. Ta4 cylindrical
and shorter or longer than ta5' Palpsl segments 2 and 3 fused (not found in other Dlsmesini).
(Ala somewhat swollen apically. Po usually biserial at mid-"8ye. VR about 8S.
Eye produced dorsomedlally. AnP, if present, either naked, aWl-like or a hirsute, blunt cone possessing a robust spine apically. IVa pubescent proximally
lind with short, perpendicular setae distlllly (upper third of coxite). MVo
clavate, setigerous, and suspended irom a more strongly sclerotized, sigmoid SVo (fig. 46-48).) • • • • • • • . • • • . • Sympotthastia
11. GonostylUs notched on dorsal margin, giving it a bllobed aspect; proximal lobe
glabrous. Darker scutal stripes often apparent.
(Eye somewhat produced dorsomediillly. LR 84, 48, 63. Palp to face 90-98.
AR 2.0-2.5; All 830 urn long. 12-17 Clypeal setae. SVo clavilte with ultra fine
microtrichia; MVo very reduced; lateral sternapodeme with fl bulbous lobe articulating with the anterior branch of the SVo; IVa slightly lobate with moderate setile. AnP, if present, hairy, cylindrical, round-"8nded protruberance
of TIX (no tergal bands) and 10 to 30 urn long (figs. 40-44.) •••• • •••••• • • • •
GOiloslylus more tubulflr, not bilobed. Scutum more uniform in color. • • •• 12
10 12. Eye produced dorsomedially. AnP a small hairy, variable projection of TIX ns in
f·gaedii. (SVo straight and joilied at transverse sternapodeme proximally and expanded
dIstnlly. AnP hairy and blunt, or narrower and up to 30 urn long. MVo ending
mace-like with stout microsetae (CIg. 1). IVo Ii simple medial bulge (not lobate).
G6nostylus linear and rugose dorsally.. Body color dark. R2+3 weak.). • •• 13
Eye rounded dorsollledially. AnP absentj TIX invaginated.
(Svo curving and joining at lateral apodemes proximally and distally narrow;
sternapodeme without knobby projections, simple; MVo truncated (fig. 45). 1V6
Ii dorsoproximallobe (Popels nose). Gonostylu5 narrowed in distal third, con!caI; also, see Pinder (1978.) i...... •...... 14
13. AR about 2.0. Gonocoxite with or perhaps without small, dorsal tubercle
projecting Over the artiCUlation of gonostylus (see Pinder, 1978). Body, upper
wing veins, legs, anteilila and capitellUm dark (body and setae more robust and
heavier sclerotlzed than f. Iberica). Body 4.0j wing 3.3 mm. LR 78, 50, 57.
VR 89. Palp to face 120. Clypeus with 12 setae •••
· • • • • • • • • • • • • • ••••••••••• f. montia Edw.
AR 1.7-1.8. Gonocoxlte with well develo[)ed toothlike tuberCle distodorsally.
Body rather uniformly dark, capitellum clear, and upper wing veins clear or
light yellow. Body 3.8 mill; wing 2.8 mm. LR 76, 54, 58. VR 93. Palp to face
about 95. Clypeus wIth 16-18 setae ••••••••••••••••••••••••••••••••
• • • • • • • • • • • • • • • . • • • • • • • • •• ~. iber.ica Tos.
14. Body dark; wing veins clear; capitellum clear. AR i.5-2.1j A3-S Wider thfin
long; A13 795 urn long. LR 86, 50, 59. tlypeus with 6-12 setae. Palp to [ace
60-80 ••••••••••••••••••••• ~. l~mgimll!la Kief.
Body very dark (shining black); wing veins darK; capitellum colored. AR 1.5 • ••
• . • . . . • . . . . • • . . . • . . .. • . . . f.. pastoris Edw. 11 PUPAE
Diamesini pupae can be differentiated from the other Diameslnae tribes
{Boreoheptngyini ahdProtanypinil, the Prodlamesinae sensu Saether and their sister subfamily, the Orthocladiinae, using Coffman (1978). Coffman (1978, 1979) expresses the following general characters for the
Diamesini: thoracic horn generally smooth and thread-like or absent, with no tracheal cOnnection with the pharate adult; anal lobe usually with only three long macrosetae near the caudolateral margin (fringe composed of very short setae in Sympotthastia only); a single row of strong thorn-like or rows of papillose spines on posterior margin of terga; fore-and midleg (tarsal portion) straight along midline between wing sheaths but hindleg recurved; and O-setae absent.
1. Posterior margin of abdominal segments IV-Vn with a single row of robust,
thorn~like and/or pointed peg-like spines (fig. 28); spinulae an conjunctiva usually not well developed. Thoracic horn long and thread-like (absent In Q. steinboecki.) • • . . • • . • • • • • • • • • • •• •••••••••••••••••••••••••• 2
Posterior margin of segments IV-VII with several rows of papillose spines;
spinulile on conjunctiva conspicuous and point anteriorly. Anal lobe always caudally projecting with tubercules next to macrosetae. Thoracic horh absent.
Anterior margin, opophyse, of I-VIII with a dark band of color. (Only L2 dorsal. L-setoe and D-setae lorked in Some species). • • • •• •••••• • •••••••••• 5 2. Terga li-IX usually with some shagreen, centrally, between the longitudinal
muscle SCilrs (M03)' 04 relatively fine nnd not extending to middle or following
segment. •• ••••.•.•••••••.••••.•••••••••••••••••••.••••• 3
Tergil without shagreen centrally 04 robust, dark; reaching to the middle of
next segment.
(Thorax smooth but with some strikingly robust setlie. Middie precorneal seta larger than others. Anal lobe with or without tUbercle. Spinulae on COnjunctiva
12 not well developed. Posterior margin of terga and sterna (III-VIn with a row of
strong spines.) •••• , '.' , •• .••••••••••.••••••••••••.•••..••••• 4
3. Anal lobe not produced to a point. 'thOrax scaly or patterned, but lacking long, robust, ·dark setae. Posterior margiri ot some sterna with a row of lIirge thorn like spines. Anteriorly pointing splnulae on conjunctiva rudimentary. Gonopodal sacs recurved upward on many species •• , • . • • •. • ••• •••• '"
••• , • • . • • • • • • •• •••••••• " Diamesa (most)
Anal lobe produced to a darkened point. Thorax smooth and possessing some
dark, strong setae. Sterna without strong thorn-like spiries. Anteriorly pOinting
spinulae on conjunctiva strongly developed. GonopodaJ sacs straight ...
...... i. . . • . . . . PseudokiefferieUa
4. Anal lobe and thorax without tubercles.Da of VIII reaching end of anal lobe.
Oonopodal sacs recurved • • • • • • •• Diamesa dampCi-gp.
Anal lObe with small, dark, tooth-like tubercleS. Thorax with a dark tubercle near dorsocentralsetae • . • • • • • • Syndlamesa
5. Anal lobe with Ii fringe oC short, thick setae (rig. 7).
(Pc-setae as In fig. 11. L1,2,4 usually split apically into 2-5 branches. Gonopodal sacs and macrosetae straight. Color of abdomen I-VIII, brown to
yellow brown and IX lighter.) • • • Sympotthastia
Anal lobe without Cringe. • • • • • • • • • • • • • • • . • • • • • • • • . • • • • • • • • • • • 6
6. Tubercle or anal lobe with some strong triangular scales Tubercle of ·anallobe without such scales •••••••••••. , •• •••••••••• 7 7. High frequency oC Corked L-setae. Anal lobe with an additional macra-seta medially and termirially Wg. 14) ••••••••.••••.•••••• , ••••••••.•••• 13 L-setae not forked (except E.. ~ Goetgh.). Anal lobe with only three caudolateral macrosetae. Large species, exuvia often over 10 mm ••••••••• Pseudodiamesa 8. Tubercle of Ilnallobe not cov.ered with scales, scales do not extend forward past the middle macroseta. L-setae short and infrequently forked. Precorileal setae (Pc) subequal iii length. Exuvia brown; muscle scars dark. . • • • •• • ••••.• 9 Caudolateral margin and tubercle covered with scales. L-setae long and frequently brllnched. Pe2, middle seta, comparatively shorter than the other two (Cjg. 13). Exuvia clear brownish-yellow. Posterlocentralarea of abdomen with about two rows oC strong spines (Cig. 9). Thorax corneOus (blistered surface). Length about 5~7 mm. • • • • •. ••• f.. gaedii Mg. 9. Tubercle of anal lobe small and relatively well scaled. L2-3 on VI-VIII and L3 on VIII bifid. Shagreen on terga ViII-IX between the longitudinal muscle scars (MD3) fine but extensive. Thorax corneous, Pc-setae light. Length about 5 mm. •• 10 Tubercale of anal lobe With few scales only along lateral border. L-setae almost never forked. Shagreen on tergum YIn reduced to a narrow posteriocentral patch; IX devoid of shagreen. Thorax smooth; P~etae dark. Color, dark brown with strongly colored lateral "keels" on VI-VIII. Length 5-7 mm. (CIgs. 10 and 12) f.. iberica Too. 10. Color light brown (fig. 8) ••••••• f.. longimana Kie!. Color dark gray • •••• • • • •••••• f.. pastoris Edw. LARVAE Head rather quadrate alid dorsum without tubercles. Color lU1eous or very dark with mouth parts darker; postoccipital margin d.ark without lateral, posteriorly directed processes. Ventromentum (the median area of mentum) with several (3) heavily sclerotized teeth, or thin and broad; or w.lth median tooth absent. 14 Dorsomentlli (lateral) teeth darker (absent in E. longimana). Ventromental plate (VMP) small, thin, obllque and teardrop shaped or heavier, shield like, or sometimes absent; VMP usually not expanded toward lateral margin of head. VMP never striate or bearded. Prementum clothed in long; flat bristles in a weakly trUobiate group. Antenna not retractile; 5-segmented; A3 conspicuously aimulate; RO baslli. Labral . lamellae (LL) usually present under the simple SI. SII simple. Pre mandible present and USUally expanded apically into 3-12 blunt teeth. Mandible usually normal, i.e., 5 teeth progressively smaller toward shoulder and seta interna (SI) dissected into usually about IS-Z0 subequal branches. Body without conspicuous dorsal color pattern caused by spinulae. Lateral setae of abdomen robust or not. Procercus usually less than twice as long as wld'r or nbsent; Cour to eight subequal anal setae (AS). Posterior parapod usually elongate with 16 dark claws. Anal tubules (TA) not longer than leg. HabItat usually lotic. Not known to be phoretic. 1. Ventromentum brolld, 7-10X first lateral tooth (lateral teeth can be absent). Premandible narrowed distally to a slmpie apical tooth, or lateral teeth, when present, small and separated only slightly from stem, or flared distally with many tine apical teeth (figs. 15-17). Procercus heavily sClerotized, button-like (fig. 18). (S-setae and spinulae over premandible simple. Premandibular brush spike-like.) 8 Ventromentlll teeth narrower and sharply defined (caution, median absent in Pagastia.) Premandible usually flared distally into 5-12 blunt teeth. Procercus, if present, cylindrical and sometimes with spurs on anal surface •• 2 2. Epipharyngeal area with five, close fitting, spatulate blndes Wg. 19). Labral lamellae (LL) under the Sis composed of many individual spines or 3-6 peetinate seales (figs. 24 or 23). Premandible usually palmate • • • • • • • • • • •. • • • • 4 15 Epipharyngeal area with more than five, narrower spines. LL composed of 2-3 plates or two pectens. Premandible large, rectilinea.r, and usually with 8-13 blunt teeth. (5-setae of labrum simple. Procereus longer than wide with 6-8 AS and two unequallnteral setne.) . • • • • • • • • • • • • • • • . • • • • • • • • • • • • • • • • • • • • • 3 3. Head squarish, often with dark postmentum. Mentum with 13 or 15 large, dark teeth; median triangular; !irst "lateral" formed by VMP and appressed to the first pair of dorosomental teeth Wg. 26). (AR 2 or 3. LL resembling two pocket combs. TA with constrictions. Large species, 10-18 mm. Species differ only Slightly from one another.) •••.•••• Pseudodintnesa Head with gula curved (Conchnpelopin-like). Median tooth of mentum absent; median formed by thick, shield-like YMP.8-10 mm. See Oliver and Roussel (1982). (Two groups: (1) AR 1.0 or 1.6, latei'al teeth of mandible compressed into a knob and Si with 5 branches, LL two, paddle-like, dentnte plates, and (2) AR 1.6, tnandible normal, LL three, nondentnte, trnpezoidal plates.) • ••••••• 4. Abdotninal segtnents with regular circlets of usually long (200-300), dark setae. Proeercal H/W 1-2. Mentum with 13 or 15 large teeth, and the median group usually compose a raised and separate nrc of rive, lighter teeth (fig. 25). LL 3- 6 identical finely pectinate sC!ales (the inost Interal ones = chaetae mediae) (rig. 2:1). Spinulae over premandible simple. Larbe supraanal and dorsolateral setae of 10th segment. (AR 1.7-2+. S-setae simple. Procercus strongly sclerotized with or without spurs and with 6-8 AS and a robust lateral seta.) ••••••••• • ••• • •.••••••.•••••.•••••• PseudokiefferieUa Abdominal segments with inconspicuous setae but sometimes longer (100-200). 16 Procetcal H/W about one or less or absent. Mentum with 17 or more teeth. LL many pointed spines with mostly separate bases (fig. 19). Spinulae oVer premandlble simple or not. Supraanal setae reduced. • • • . . • • • • • • • • • • 5 5. Procercal H/W 0.7-1.0 with a strong anteriorly placed lateral seta on the procercus itsel! and 5-7 AS. • • • • • • . • • • • • • • • • • • • • • • • • . • • • . • • • • • 6 Procercal H/W to about 0.5 or procercus entirely absent. When present, no lateral setae present on the procercus but a seta present forward on body, occasionally with smaU spurs anaUy, and usually with 4 AS. (Labrum (fig. 19); sm variable; LL varied groupings of 10-25, but up to 40, nat (rectangular in cross section), often individual, hooks (fig. 24h chaetae mediae dentate, spinulose or plumose (figs. 20-22); splnulne over premandlble cut Into several points. Premandibularbrush a unlserial loop of fine bristles. Mandible normal, or the distal two or three teeth tubular and subequally large. Posterior parapod elongate; TA shorter thilil leg. Body 4-10 mm. Two groups can be separated: (1) procercus present, It only a wedge oC sclerotization anally, AS usually long (250-350), AR 1.5-2.3, often a medium sized species, and (2) procercus absent, AS short, thick (usually less than 100 but as much as 200 long), AR 1-1.8, often a small species.) •••••••••••• • •.••.••••.••.• • . Diamesa (most) 6. Labrum and premandible as in Diamesa (couplet 5). On AZ, style much larger than inconspicuous lauterborn organs; on At, accessory blade 2/3 as long as blode (typical of Diamesa). (SlIi simple. AR 1.7-2.0. Median or mentum about 3X wider thiln Cirst lateral tooth. Procercus without spurs; she AS about 200 long. SuprBl!nal setae reduced. Abdominlll segments with rather long (140-210) setae. 10-12 mm.) .• • "• ••••••• ; ". • • • • • . • • • • • • • •• Diame$!i damp.f(-gp. 17 LL n compact row of ·20 simple spines (more rounded in cross section). ~etae simple. Most spinulae over pre mandible simple, but some may be bifid. Accessory blade very reduced. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 7 7. AR 2.2-3.0. Mnndlble normal. Premimdible palmate with about 6 teeth. Ventra mentum with three subequal teeth that are slightly or very mlich larger (wider) than appending lateral teeth (17-19) teeth total). Procercus with robust lateral seta nnd tendency to have terminal spur. Abdominal segments with long (about lOO), conspicuous setae. Large, 10-13 mm. (~. nigra Ros. with three very large median teeth; style of A2 reduced and subequal to lauterborn organs; triangular chaetae media; premandlblilar brush spike-like with few dissections apically. ~. nigra and mira Mak. with the lower AR, 6 AS (200 long), VMP C1aring out somewhat lnterally, and dark postmentum. §. hygropetricn Kief. with a mare normal ventram·entum of small teeth, an AR 3, aild 5 AS. Style, VMP and chaeta media as mentioned alSo may be diagnostic for the genus.} • • • • • • • • • • • • • • Syndiamesa AR 1.0-104. Mandible with the three distal teeth large and subequal. Premandible constricted distally, having about three teeth. Ventra-mentum with medinn tooth very recessed and the next two pairs of teeth largest, towering OVer the remainiilg 7-8 pairs of lateral leeth. Procercus with 7 AS (200 long) and small lateral setae. Abdominal segments without conspicuous setae. Style larger than lauterborn organs and reaching mid A4- Small arctic species, 5 mm. See Maknrchenko (1978) and Tilly (1978: fig. 7). _ •• • •• • • • • • • • • • • • • • • • • • • • • • • . • • • • • • Arctodiamesa nppendiculata Lundst. 8. Mandible not normal. Pre mandible with five or with many Cine teeth /lpic/llly •• • • •• • •• • • • • • • • • • • •• • • •• • •• • • • •• • • • • • • ••• • • • • • • • , • • •• • • 9 Mandible normal. Pre mandible simple, with a broad /lpical tooth Or with /l broad a~illal tooth and 1-4 inconspicuous lnteral teeth. • • • • • • •• 10 18 9. Ventromentum dissected into five unequlll sections; VMP hairless but expanded and rounded laterally as in Odontomesn; six to seven pairs of Jaterlll teeth (fig. 27). Antenria near f.. ibericai AR 2.2. Labrum adorned with many strong, simple spines on level with S-setae. (Epipharyngeal area with 14-18 similar spines. Spinulae over premnndible truncate. Premandible weakly digitate apically, with five teeth. Mandible with distal , three teeth large, subequlll and Si with i6 very plumose branches. Maxillary galea withOut a row of blades. Prementum beset with short hairs! Procercus more cYlindrical with 6 AS 270 long and a robust lateral seta. Abdominill segment 10 with a strong ventral seta (130 long). Supraanals reduced. fi mm. Southi!astern USA.) ••• • •••••.•••••••••••••••••••••• Genus P Many head structures reduced: Mentum without laterill teeth or YMP. AR 0.5. (Sn Ilnd SIll fine, hairlike. SIVB longer than SlY A and an additional pair or socketed setae near !abral margin and another above. LL abSent? PE reduced. Mandible without apparent lateral teeth or seta intema. Premnndible broad apically with 15 serrations (fig. 16). Procercus, a strongly sclerotlzed button with usually 7 AS (about 220 long) and a lateral seta that is about one third as long. Slipraarials subequill to AS; dorsolateral seta of 10th segment (base of parapCfds) much shorter than supraanals and longer than the ventral se ta of 10th. 8-11 mm. Photo of head, Simpson and Bode (1980:29).) • • • • • • • • • •• 3 Potthastia longiinana KieC. 10. Ventromentum lOX flrst dorsomental {Iaterall tooth. Maxillary galea with five lanceolilte blades (figs. 32 and 37). Premandible simple, with a broad apical tooth (spoonshaped) nnd without laterill teeth. (Mandible siekle.,like (fig. 31), A2 unequally bifid (fig. 29), and usually 6 AS.) •• •• , •. • •••..•••• • • '••..•• • .•.•••••.• ,...... 11 19 Ventromentum 7X first dorsomental tooth. Galea without blades. Ptemandible with 1-4 small lateral teeth (fig. 17.) ••••••••••••••••••••••••••••••• SYnipottl)astia 11. Heae yellow, no mncuiulli on frontoclypeus. AR 1.5-1.7. Mentum with light colored median and seven pairs of dark laterals. (Maxillary palp somewhat eiongate (fig. 37). Dorsolateral setne oC the 10th segment very long, subequal to the AS which are 20% shortel' than the supraanals. Procercus with j; AS (170 long) and a lateral seta nearly at apex that is 2/3 as long. Six or 10 mm. Photo of head, Simpson and Bode (1980:30).) ••••••••••••••.••••••••••• Potthas tia gaedii Mg. Maculum on frontoclypeus. AR 2.0. Ventromentum dark. (Figs. 29~36, 38 and 39.). • . • • • • • • . • • • • • • • • • • • • f.. iberica Tos. Potthastia iberica Serra-Tosio Potthasti.a iberica Serra-Tosio, 1971b:160-166, six figures. A mature male pupa from Georgia made it possible to link males from Wyoming with the original description of a male of iberica discovered in the Spanish Pyrenees. A mature female pupa froni Idliho with larval skin made it possible to describe the temale and the iarvae. Adults confOrm very closely with the description by Serra-Tosio (1971b). Nearctic male specimens have appendage parts that afe 5-10% larger, but it is not unusual for ncnrctic examples to be larger and darket (dC. Oliver, 1959:62, e.g.). Moreover, the TIX imd clypeus had more setae, and the SV ratio of P2 attained 4.1. Subsequent rearing of a larva froni Wolf Creek, Vogel StatcPark, Georgia, genere:Uy conformed to the following descriptions but was not inCluded in them quantitively. Serra-Tosio (1971b) did mention a setigerous median volsella (aedeagus). He confirmed my drawing as aceurate (Serra-Tosio, pers. COnim.). FUrthermore, his 20 drawing very probably represents a teneral male since the aforementioned rearing has volsellae andapodemal configuration exactly as depicted by Serra-Tosio (1971b: fig. 6). Pemale (One mature pupa; fig. 2.) Characters for the genus as derived from the type, f. longimalia, by Saethllr (1977) are as follows: "Gp vrn large with ventrolateral lobe emarginated ali caudomesal margin and partly covering dorsomesallobe. Apodeme lobe vestigial. GP IX well developed; notum very short, less than half as long as ramus. T IX of medium size, setigerious protrusions tranverselY oval. Transversely, approximately oval plate anterior of postgenital plate partly closes vagina caudally. Segment X without setae. Postgenital plate well develoPed; characteristically shaped. Cerci relatively large. Labia broadly tongue-shaped, without microtrichla. Three seminal capsules with weak microtrichia. Spermathecal ducts with weak curves". The female specimen Crom a mature pupa from Idaho conforms to this diagnosis and resembles closely the figures presented by Saether. It has coloring, head and thoracic characters like the male, but it has six flagellomeres with reduced plumosity and the term [nalia as Cigured. Pupa (Two male and four female exuviae; figs. 10, i2.) Differential characteristics are reflected in the pupal key above. Measurements in micrometers. Setal length not given as mean but only as the best representative example (sample size and measurable condition of setae poor). Length of male 6-6.5 mm; female about same, but one over 7 rom. Uniformly tapered abdomen. Color uniformly dark (gray) but with a darker anterior band, muscle scars, and lateral keels on abdominal segments. All setae short and dark. CephalothoriIX. Cephalie tUbercles not noticeable, setae in their place about 200 long. Thor·acic horn absent; its spiracle base, a smooth, dark knot. Precorneal setae short and dark; Pcl subequal to Pc2 (about 100 long);'Pc3 thicker (1 urn) alid about 120-130 long. 21 Thorax smooth and relatively uniform color. Wing sheath without pearling. A branched dorsocentral seta located over the thoracic spiracle on male and female. and one other simple or branched seta medially. One medial antepronolal. Abdomen. L-setae short, dark and almost never Corked. Female shagreen similar to male except posterlocentral spines not as robust as in male. Shagi'een on tergites U-VIi continuous centrally {between the longitudinal muscle scars), from the dark anteriOr band (apophyse) to the posterior margin. Splnulae increasing to papillose spines rearward and running into the anteriorly poInting. intersegmental spines of about equal size on II/lII-V IVI. Spiracle present laterally at the bottom of the upper third Of terga I-VII. L-setae lI-VlII otten very near lateral margin. Ll ventral and located near spiracle; LZ. dorsal and near Lli L3 and L4 ventral and on lower third. D-and V-setae rather small. simple. Gonopodlil sacs of males sometimes clavate, extending past Claudal margin. Shagreen. Tergite (::T) 1 with a posterlocentral group of polygonal islands; sternite free of such markings. Tergites II-VI with spinulae uniCormly spaced and sized, and starling at the anteriOr band and covering most of the central area between the longitudinal muscle scars (MD3). Spinules increase in size to very small papillose spines at the D3s, and continUing to increase in size until meeting the reverse pointing spines oC sUbequal size on the conjuntiva. These spines arc largest centrally between the D5S. this central area with four or five rows or shOrt (about 7 long) triangular spines. A narrow spineless (some poiygonal islands only) area between the two groups of opposite-pointing spines. A paired group or muscle scars (MDZ) consisting of 3 or 4 dark spots on lowest third or tergite beginning near the D3S; theSe flaring out anteriorly and demarcate a slight channeling of the posteriocentral shllgreen. "ChanneUng" more apparent on subsequent segments. Upper third of segment with a paired group of scars (MDI) consisting of two or three lighter spots that flare in opposite direction. 22 Sternlte (=S) II-VII with one central pair of muscle scars (VMD2) (140-160 urn apart). Shagreen delimited by Mb3 and VMD2 s~ars. SII, spinulae orbiting VMD2 from anterior band to about Va. sm, a trianguiar patch from the MD3 to VMD2. SIV, a small triilngle of spinulae laterad to VMD2, narrowing posteriorly; a small patch of small papillose spines in about three rows on last third between V4 and V5. SV, a few spinulae above VI and a patch of papillose spines between V4 and Vs as on SIV but wider in extent. SVI and SVlI spinulae extend In a narrow strip from the anterior band between VIS to the V3 and V4,and here larger spines (approx. six rows) spread laterally underneath the V3 and V4, and extend to the posterior margin. Also a small patch of spinulae on anterioiateraimargin at SV) and a stronger patch on SVII. Segment VIiI (fIg. 10). Tergite with posteriocentral patch of strong s"pines with only a few spinulae running anterIorly between MD2. MOl absent. svm, extensiv"e sh"agreen from anterior band, narrowing to V3, then a set of strong spines (5-6 rows) expanding again laterally and reaching posterior margin. VMD2 absent, but a circle of small white dots, centrally. Anal lobe devoid at shagreen. Tubarcle with a few rows of small triangular scales on lateral margin; see fig. 10, Inset. Setae. On 1, LI and L3 80. On II-VlI, Ll-4 present whereas L1;2,4 subequal 70-85 and Lj shorter, about 50. On VllI, L1 and Li near posteriolateral corner and about 75, L3 and L4 on conjunctiva at spurred corner, Ll-3 more rObust than on previoUS segments (L3 in this ease is probably L4)' Oce8Sionally an Ir or D-seta seen apically Corked on VIII. Macrosetae of anal lobe straight, subequal (220). On VI, for example, D2. 3 and 5 tending to form straight line. DZ and D4 subequal (65) and somewhat larger than rest. D4 not oilerreaehing posterior margin. Vl In line with V3) V4 next to V3, and V5 well sepa.rated and loeated in the 23 posteriocentrnl shagreenation. V3 largest (55) others smaller, subequal. V-setae a bit shorter than the D-setae. Larva (4th stadium; figs. 29-34; 36-39.) See key to the larvae above for separ·ational characters. Measurements in micrometers, giving mean, standard error of mean (std. deviation divided by square root of n) and n in parentheses. Head. Squarish: Max:imuiIi width 370~380; length (apex of mentum to dorsal postoccipital margin) 420~500. Mouth parts and postoccipital margin black. Frontal opotome with a dark, oval nlaculum. Mentum. Width 123+ 2 (12). Ventromelitum area broad, flat, black edged and unequally trisected, and lOX the first dorosmelital (laterall tooth. Nine pairs of dark, rounded lateral teeth (fig. 36). Prementum with long, flat hairs forming three bundles (typical of Diamesini); its palp with three members (fig. 34). Antenna. Lengths of sclerotized segments (AI-AS!: 58.S': 0.8 (12), 14.4': 0.3 (11), 7.1:' 0.3 (10), 2.4 .: 0.0 (IO), and 4.8': 0.1 (9). AR 2.0 .: 0.2 (AR of 3d stadium 0.7); ALAW 3.4. As with f. gaedii, blade reaching mid A4 to AS and accessory to mid A3' Style on A2 reaching AS' Lauterborli organs subequal and inconSpiC!uous. Ring organ at 11 from base; sense pits, one near RO at 13, another at 30 on specimens from Georgia but at 47 on specimens from Idaho. Antenna: mandible: premandlble '" 1.2:2.1:1- Labrum. Depicted in fig. 38. Structures transparent-yellow or milky. SI short (15 urn), spatulate, SIT and sm hairlike and subequal; srv A and B subequal, short bl8des (not peg~like). A group of simple chaetae on each side Of labral rod, and the chaeta media proximal to 51 with a larger base and perhaps several unequal branches. Spinules over premandible, a group of four simple scales increasing in size medinlly. A transparent, rectilinear I8brallamella under each SI may be present. 24 Pecten epipharygeill area. PE three short pegs (fused?), about 5 pairs of ChL, the most medlill ones swollen apically; two pairs of peg-like basal chaetae. Ungula and basill sclerite normal in appearance. Premandible. Length 70:: 0.9 (11). Apicill tooth broad, darkened, spoonlike with ribs on inner curvature. No laterill teeth. Stem robust. Brush, a simple spine (fig. 30). Mandible. See fig. 31. Note that the four laterill teeth are subequal and appear as a subunit Instead or individual outgrowths. Seta interna with 16-18 branches that ilre finely plumose) mostly on Inner border. MaxUla. Galea with five lanceolate blades. Chaeta of lilcinia simple and sub equal, but one next to the sensilla basiconica, the anterior lac inial chaeta, narrowly rectangular and possessing a short apical tuft. Pilip a low ring (fig. 32). Body. Length 5.9 :: 0.3 mm; but up to 8 mm. Lacking outstanding body setae. Brownish in mount. See fIg. 39. Procercus. HI'" 70%. Strongly sclerotized, button-like, with a vertical band of reinforcing chitin anillly and running in a narrow rib below the button. Seven anal setae apically, 233 :: 7 (8) long; two unequal IllleTal setae. Suprsanal setae 128 .t 9 (10) long and as thick as anal setae. Anal tubules 405 .t Hi (5) long, rounded distally. Anterior parapod. Separate with claws In contiguous series. Three apical rows Of gently curving, long claws, hooked sharply at very end; a middle row of claws hooked sharply over their bases and with two Inner teeth; four rows of similarly hooked claws but growing progressively smaller and having one inner tooth; and most proximally, scattered shar[l splnulae of reducing size. Posterior parapod. 16 simple, dark claws. Venlrobasal and dorsolateral setae of 10th segment not conspicuously long, 54 :: 3 (6) and 97 : 5 (3) respectively. Length (jnClluding basal 10th segment) 371 .t 25 (11) hut as long as 500 (poor measuring condition). 25 Material. Georgia. White Co., Chattahoochee R. ilt Helen, Hwy. 356. 340 43'N 830 4S'W. Alt. 470 m. 4th stadium (1); Union Co., Wolf Cr. just above L. Trahlyta at Vogel S.P. (Nottley R., Tenn. drainage) 340 46N' 830 SSW. Alt. 700 m. 4th stadium (3) and 3d? stadium (1), and a mature male pupa (UMC). All call. B.A. Caldwell on 22 Apr. 1981, from drift. Also, larva-pupii-teneral male rearing, 27 Feb.- 3 Mar. 1983, coll. of author. Idaho. Adams Co., Last Chance Campgd., 5 mi E. of New Meadows. Rocks in 8-30 em, moderate current. 4th stadium (8), 3d? stadium (2), and a mature female pupa with larval skin. All leg. D. Hansen on 20 Sept. 1967. UMC! VMw 14.932. Wyoming. Johnson Co., So Fork Campgd., 12 mi S. of Buffalo. 44 0 17'N, 1060 S7'W. Alt. 2260 m. Pupal exuviae: male (2) female (3), on 2S Aug. 1968. A teneral male from drift at 6 p.m. on 23 Aug. 1968, UMC: DH69-102j a male obtained sweeping from Clear Cr. Ilt dusk, DH69-251; and t1 male hypopygium, DH69-253. AU leg. Hansen. Ecology. The habitat of f. iberica appears to be similar to f. gaedii in the eastern USA. Larvae are found in easlern and western upland streams (500-2,300 m altitude) On rocks in moderate current and Open canopy. 'typical of many Diamesini, they appear to be scrapers of periphyton. Distribution in the Pyrenees is noted by Laville (1980). He indicated Iberica was found with preponderant Orthocladinae in the eastern Pyrenees at 1,500 m but more peculiarly in a lowland, western coasttil tributary at 400 m. Associated here are the Harnishia-complex and SYmpotthastia spinlfera which ' implies to me a sandy, coastal stream. 26 Attempts to capture and rear this speeies from Wolf Creek at Vogel State Park, Georgia, Cailed in Del!ember 1981, March and July oC 1982, but finally succeeded 27 February 1983. Associated organisms iii these laler drift samples, with nibble being disturbed above net, showed a sparse popUlation of Tvetenia baliaricn-gp., EuortlJoeladius sp. i, Cricotopus sp., Diamesa nivoriulida Fiteh, Q. cr. spinaeies Saether, and heptagenlids were eommon. These samplings suggest that R. lberiea is "succeeded" by Euorthocladius sp. 2 in Spring and by Cardiocladius prob. obscurus Johannsen in Summer. Wolf Creek seems to nuctuate from having many species to few, but in sparse populations. Both sites in Georgia are cool, soft-water, trout-quality streams. Data from 1976-1979 disclose that the Chattahoochee River at Nacoochee, Georgia (neat Helen) to have a pH 6.1.-7.0, specifie conduetance below 20 microsiemens, BOD 0.3~0.8 mg rl, dissolved nitrogen about 0.04 mg 1-1, and dissolved phosphorus usually below O.OZ mg 1-1 (U.S. Geol. Surv. Water-Data .Report, annually). 27 ACKNOWLEDGMENTS Dr. Dean Hansen loaned me many of his elegant specimens from the University of Minnesota collection (tiMC). My thanks t.o Dr. P. S. Cranston for communicating features of f .. .!!!£!!!!.! Edw. from a syntype. I appreciate Dr. Bruno Rossaro's discl.osure of larval characteristics of Syndiamesll. and Q. dampfi-gp. that were not presented in Ferrareseilnd Rossaro (i9Bl) and gift of ~. nigra larvae. The holotype of ~. iberica was not available Cor this study; however, I am very fortunate to have gained Dr. Bernard Serra-Toslo's permission to reproduce his excellent drawings (figs. 28, 40-53 herein). 2B REFERENCES Brundin, L. 1966. Transantarctic relationships and their significance as evidenced bychironomid midges •••• K. svenska Vetensk-Akad. Handl. 4 ser. 11(1), 472 p. Coffman, W. P. 1978. Chironomidae. Pp. 345-376!!l R. W. Merritt and R. W. Kendall/Hunt. Dubuque, Iowa, 441 p. _____• 1979. Neglected characters in pupal morphOlogy lIS tools in taxonomy and phylogeny of Chironomidae (Dipteral. Ent. scand. Suppl. 10:37-46. Doughman, J. S. 1983. A guide to the larvae of the nearetlc Diamesinlie. The genera Boreoheptygla, Protanypus, DiamesB and PseudokieCCeriella. U.S. Geol. Sut-v. Water-Res. Investig. Rep. No. 83-4006, 58 p. Edwards, F. 1929. British non-biting midges (Diptera; Chironomidael Trans. ROyal ent. Soc. Lond. 77~302-307. Ferral'ese, U. and Rossaro, B. 1981. Guide Per n Riconoscimento Delle Specie Animlili Delle Acque Interne Italiane 12. Chironomidi, 1 (Diptera, Chironollfidae: Generalita, Diamesinae, Prodiamesinae). Consiglio Nazionale Delle Rlcerche, AQ/l/129, 97 p. Goetghebuer, M. 1932. Dipteres ChirOnomidae IV. Pp. 144-188!!l Faune de France 23,Soc. Sci. Nat.; Paris, 201 p., 23, Soc. Sci. Nat., Paris, .201 p. 29 Honsen, p~ C. and E. F. Cook. 1976. The systematii:!S and morphology of the Nenrctic species of Diamesa Meigen, 1835 (Diptera:Chironomidae). Mem.oC the Am. Entom. Soc. 30:203 p. Johannsen, O. A. 1937. Aquatic Diptern. Part m. Chironomidae:subCamilies Tanypodiime, Dlamesinae, and Orthocladiinae, N.Y. Agr. Expt. Sta. Mem. 205:84 p. Kownacki. A. 1981 Genus Syndiamesa Kieffer 1918 (Diamesiilae.Chironomidne, Diptera)... Acta Hydrobiol. (Krakow) 23(4):381-398. Laville, H. 1980. Inventaire 1980 des Chironomides (Diptera) corinus des Pyrenees. Annis. Limnol. 16(3):211-223. Lundstroem, C. 1918. Diptern-Nematocera nus den arctischen Gegenden Sibiriens. Mnka'rchenko, E. A. 1978. Soine species of Dinmes8 Meigen (Diptera: Chironomidae) from the Chukotskii Peninsula. Soil Biology Inst. of the Soviet Far East Research lnst. 49(152):56-62 (in Russian). ___~. 1980. Two new species of Parapotthastia (Diptera:Chironomidae) from the south of the Soviet Far East. J. ZoOl, USS'R, 59(3):466-470 (in Russian). Oliver, D. R. 1959. Some Diamesini (Chironomldne) Cram the Nearctic and Palaearctlc. Ent. 'I'idskv. 80:48-u4. (Cor Pagastia and Pseudodlaml!S8) ____.• 1981. Chironomidae Pp. 423-458 !!! Manual o.f Nearctic Diptera Vol. 1 Agr.iculture Canada Monog. 27. 30 Oliver, D. R. and M. E. Roussel. 1982. The larvae of Pagastla ... Can. Ent. 114(9):849-854. Pagast, F. 1947.Systematik and Vetbreitung der urn die Gattung Diamesa gruppierten ChirOnomidae. Arch. Hydrobiol. 41:435-596. Pankatrova, V. Ya. 1970. Larvae and pupae of midges of the sUbtamily Orthocladiinile of the fauna of the USSR. Nauka (Leningrad) 102, 345 p. (in Russian). Pinder, L. C. V. 1978. A Key;to the Adult Males of the British Chironomidae (Diptera) the non-biting midges. Freshwater Biological Association Scientific! Publication No. 37. 2 vols., 169 p., 189 pIS. Roback, S. S. 1957. The immature teildipedids of the Philadelphitl area (Diptera: Tendipedidae). Monog. of Acad. Nat. Sci., Philad. 9:152 p. Rossaro, B. 1980B. Description of some unknown larvae of DiB.mesa genus Bnd corrections to previous descriptions (Diptera, Chironomidae) Arch. Hydr6biol. 9iJ(3};298-3iJ8. __. __ • 1980b. Syndiamesa nigra n. sp., daUe Alpi italiane (Diptera: Chironomidae) BoU. Soc. Entom. Ital. 1i2(9-10):192-198. Saether, O. A. 1969. Some nearctlc PodonominBe, Diames(nae, and Orthc'rc"Iadlinae (Diptera: Chironomldae) Bull. Fish. Res. Board Can. 17 0; 154 p. 31 _~ __• 1976. Revision oC Hydrobaenus, Trlssocladius, Zalut,schia, Paratriss ocladius, arid some related genera (Oiptera: Chlronomidae). Bull. Fish. Res. Board Can. 195, 287 p. ~ __...c. 1977. Female genitalia in Chiroriomidae and other Nerliatocera: morphology, phylogenies, keys. Bull. Fish. Res. Board Can. 197, 209 p. ___...c. 1979. Hierarchy of the Chironomidae with special emphasis on the female genitalia (Diptera). Ent. scand. Sup pl. 10:17-26. ____• 1980. Glossary oC chironomid morphology terminology (Dlptera: Chironomidae). Ent. scand. Sup pl. 14:1-51. SaewedaJ, L. 1982. Distribution of leg sensilla chaetica In male Chironomidae (Dipter.a, and its phylogenetic significance. Ent. scand. 13:1-22. Serra-Tosio, B. 1964. Quelques Diamesini (Diptera Chironomidae) du Dauphine et du Vivarais. Description de quatre especes nouvelles. Trav. Lab. Hydrobiol. Piscic. Uliiv. Grenoble 56:29 ~ 52. _ .__ • 1961. Taxonomie et ecologie des Diam~B du groupe iatitarsis (Diptera, Chironomidae). Trav. Lab. HydrobioJ. Piscicult. Univ. Grenoble 57-58:65-91. 32 __._. 1968. Taxonomie phylogenetique des Diamesini: lcs genres Potthastia Kieffer, Sympotthastia Pagast, Parapotthastia n.g. ct Lappodiamesa n.g. (Diptera, Chironomidae). Trav. Lab. Hydrobiol. Piscicult. Univ. Grenoble 59- 60:117-154. ___• 1970. Les Oiamesa du groupe dampCi. Description d'une espece nouvelle (Diptera, Chironomidaei. Trav. Lab. HydrobiOI. Plscicult. Univ. Grenoble 61:107-146. _.___ • 1971a. Contribution a l'etudc taxonomique, phylogenetique, biogeograpfique et ecologique des Dlamesini (Dlptera, Chironomidae) d'Europe. 2 vols., 462 p., 183 pis. These presentee a l'Universlte S~ientinque et Medicale de Grenoble. ___• 1971b. Deux Oiamesini nouveaux d'£Spagne (Diptera, Chironomidae). trav. Lab. Hydrobiol. 62:147-167. ___• 1916. Chlronornides des Alpes: Le Genre Pseudodiarncsa (Dlptcra, Chironomidae) Trav. Sci. Pare Nat!. Vanoise 7:li 1-138. Simpson, K.W. and R.W. Bode 1980. Common larvae oC Chironomidae (Diptera) Crom New York State streams and rivers. N.Y. State Mus. Buyll. 439:105 p. State Sublette, J. E. 1964. Chironomid midges of California. II. Tanypodinae, Podonominae, and Diamesinae. Proe. U.S. Nat!. Mus. 115:85-135. 33 ___• Type specimens of Chironomidlle (Diptera) in the Canadian National Collections, Ottawa. J. Kans. ent. Soc. 40:290-331. _ . __• 1967b. Type specimens oC Chironomidae (Diptera) in the Cornell University Collection. J. Kans. ent. Soc. 40:477-564. ThierieMllnn, A. 1944. Bestimmungstllbellen Cur die bis jetst bekilnnten Larven und Puppen der Orthocladiinen. Arch. Hydrobiol. 39:551-664. ___• 1952. Bestimmungstabellen fur die Larven der mit Diamesa nachst vetwnndten Chironomiden. Beitrage zur Entomologie 2(2-3):244-256. Tilley, L. J. 1978. Some larvae of Diamesinlie and Podonominae, Chironomidile from the Brooks Range, Alaska, with provisional key (Dlptera). Pan-Pacific Ent. 54(4):241-260. Willassen, E.1982. Descriptions and redescriptions of female Diilmesa Meigen, 1835 (Diptera:Chironomidile); with a comparative morphOlogy keys, phy!o-gerietlc and biogeographical notes. Dr. scient. thesis., Dept. Syst. Mus. Zool. Univ. Bergen, 316 p. Wuelker, W. 1959. DiaMesarien-Studien (Dipt., Chironomidae) im Hochschwarzwald. Arch. Hydrobiol./Suppl. 24(3-4):338-360. 34 CAPTIONS Figs. 1-4. Potthastia iberi\:a Serra-Tosio: I, Hypopygiurn showing endoskeleton. Note the medial "longitudinal" apodernes; also, note the distodorsal tubercle of the gono(!oxite. Scale 46 urn (IVo, inferior volsella; LSa, lateral sternapoderne; MVo, median volsella; Pi terminal peg of gonostylus; Pha, phallapodeme; SVo, superior volsella; t, tubercle on gonocoxite; TSa, transverse sternapodeme; Vi, virga.) 2, Caudal region of female. Left side ventral vIew; right dorsal view. Scale 75 urn; 3, Thorax, dorsal view showing closed commissure. Inset showing open commissure of Pilgastili. 4, Wing. Fig. 5. Gonostylus of Syndiamesa edwardsiPag. Fig. 6. Gonostylus oC Pseudodiamesa. Figs. 7-10. Pupal exuviae, eaudnl sections. Scale as shown: 7, Sympotthastla zavreli Pag.; 8, Potthastia longimana; 9, f.gaedil Meig.; 10, f. iberica. Figs. 11-13. Pre corneal setBe showing relative size relationship: 11, Sympotthastia; 12, f; iberica (or longimana); 13, f. gaedH. Fig. 14. Pupa exuvla, (!audal, of PegasUa orthogonia Olivo Note medio-terminal simple setal pair; this is branched for particD ROb. and orlentaiis Chern. 35 Note inset depicting papillose spine surrounded bya clear field which is not the form found with those listed above. Scale as shown. Figs. 15-17. Pre mandible, apical: 15, Form for f. gaedii, 16, f.. longirnana; 17, §. zllvreli. Fig. 18. Proccrcus of the sister genera PotthllJltia/Sympotthll$tla. Fig. 19. Labrum and epipharyngeal arell of a Diamesll' Note separate but close-lying lamellae Under SI's and, just lateral, the differential-form chaetae mediae and, then at the lateral margin, the cut spinulae. Figs. 20-22. Chaeta-medial forms found on labrum of Diamesa. Fig. 23. Chaeta-medial and lamellar form found on labrum of PseudokieIferiella. Fig. 24. Lamellar forms of Diamo:sa. Note bases are rectangular. Pigs. 25-27. Mentums: 25, PseudokiefCeriella; 26, Pseudodiamesa; 27, Genus P. Fig. 28. Caudal section of a typical Diamesa pupa (Serra-Tosio, 1971a). Figs. 29-36. Larval head parts of E.. ibericll' Seale 20 urn. Self-explanatory. (Pigs. 33 and 37 deleted.) Fig. 35. Maxilla of f. gaedii. Scale 12 urn. Figs. 38 and 39. E.- iberica, 38, Labrum. Seale 14 urn. (Chaetae and spinulae on left exaggerated.); 39, Gaudal section. Note strong setae, distally, on the bifid 10th segment (base of pariipodsl; dlb, dorsolateral bristle. AS, anal setae; Sa, suprilanalsela. 36 Figs. 40-53. Hypopygia (Serra-Tosio, 1971a): 40-44, Po.tthostia glledilj 41, anal point variations; 42 and 43, other views or gonocoxite and gonostylus; 44, phnllapodelre (note its continuity with the rrodified SVo and lack of fi not iceable MVo which is present in~. iberica. This configura t i on approaches Dinrrcsa); . 45, f. iongimana, apodeines; 46-48, Sympotthastia z8vreU; 47, aedeogattobe; 48, enlargement of goJ\ostylus; 49, Pseudokii!rCerletta parva; 50, Lappodiamesa brund!ni; 51, Pseudodiamesll. branickii; 52, Diamesa dompCi; and 53.. Syndlamesa edwardsi. 37 ...... ~ ,.' • • • • • • . •• -'." •• l . / ""'>..... : '~ --:'-' ---- ...-Nei! \ 15 18 25 26 , ... , '.: I -.;,;. , ~ ... I 3& 1 1 , , )/; ~'1 t.:.''':\... ·. 1I~ k ·~ I,.':. ~) ~ . ~ ' :: ~ 37 "~ -- {3-~ tJ ...... , It) !::L ".10 ;0 .J -