THE GENUS DIMORPHOPTERYX. - By S. A, RoHWER

SYNOPSIS OF THE SPECIES OF SAWFLIES BELONGING TO THE GENUS DIMORPHOPTERYX.

By

S. A,

RoHWER,

OftheBureauofEntomology, UnitedStatesDepartmentof Agriculture.

The North American

speciesbelongingtothe

genus

Strongylogaster

and

tothesectionpinguisinNorton'sclassification

were made

intoa

genus by Ashmead

in his synopsisof the genera of sawflies.

For

a

number

of years

aU

the species

belongmg

to this

genus had been

assembled

under one name, and

biological notes

on some

of

them

published

under

that

name. In

1910 melanognathus

was

described

from one specimen from New Brunswick, Canada, and

in 1911

Rohwer

^{^}tabulated thespecies

and

characterized certain

forms

as varieties.

Recent

rearings

and more

careful

study

of the adult

brought

three

new

species to light

and

also

emphasized

thespecific identity ofthe

forms

treated as varieties inthe last-mentioned paper.

ITiis

paper

is a contribution

from

the

Branch

of ForestInsects,

Bureau

^of

Entomology.

Keytothe species.

Scutellum strongly convex; transverse radius wanting;mesoprescutum rufous;

basal platespale abnormisRohwer,p.446.

Scutellumnot stronglyconvex;transverseradius present;mesoprescutumblack;

basal plates black orbrown 1.

1.Fourapicalabdominal segmentsblack; (mandibles,antennae,clypeusand labrum

black) melanognathusRohwer,p.446.

Abdomen

beyondbasal plate paleexceptsometimessheathisblack 2.

2.Females(scutellum yellow) 3.

Males(scutellum usually black,thoughinonecase,yellow) 7.

3.Apicalmarginoftheclypeusdepressed; (clypeussubsquarely emarginate; lobes rectangular;the anteriormarginpale;four anteriorfemorapale).

erransRohwer,p.446.

Apicalmarginoftheclypeusnot depressed 4.

4.Anteriormarginoftheclypeus arcuatelyorsubangulately emarginate; lobestri-

angular 5.

Anteriormarginoftheclypeus subsquarely emarginate; lobes rectangular 6.

5. Antennaeblack;ocellarbasinjust belowthe ocellus shining, evenlyconcave,

fanshaped virginicaRohwer,p.446.

Antennaepale;ocellarbasinjustbelowthe ocelluswithafurrow in thecenter.

pinguis (Norton),p.447.

1Proc.U.S.Nat. Mus.,vol.41,p. 403, etc.

ProceedingsU.S. NationalMuseum,Vol.

48—

No.2081.

445

446 PROCEEDINGS OF THE NATIONAL MUSEU3I.

vol.48.

6.Anteriormarginoftheclypeusyellowish;antennaepiceous;mesepistemumwith a pale spot basally;tibiaeblack apically autumnalisRohwer,p. 447.

Clypeusblack; antennaeblack;mesepistemumblack; apexoftheposterior tibiae

black castaneaeRohwer,p. 447.

7. Fifthtoeighthantennaljointswithouta ventral apicalcurvedprojection; post- ocellarareaandarea latradofthelateralocelliwithoutlargepunctures; (clypeus shining,subangulately emarginate; supraclyi^eal area convex,notmoundlike;

lower angleofcheeknotproduced) virginicaRohwer,p. 446.

Fifthtoeighthantennaljointswithacurvedventral apical projection; postocellar areaandarea latradofthe ocelluswith largepunctures 8.

8. Scutellum witha pale spot; apicalmarginoftheclypeuspale;antennaeentirely pale;lower angleofcheeknotproduced; (clypeusbroadly subsqxiarely emargi- nate; lobestruncate;supraclypeal areaconvex) quercivoraRohwer,p. 448.

Scutellumblack; apicalmarginofclypeusblack; antennae,exceptapices, pice-

ous;lower angleofcheek produced 9.

9.Supraclypeal areaflat;^vingsdusky;apicalsterniteblack,.erransRohwer,p. 446.

Supraclypeal area convex, ingeneral outline triangular;wings hyaline; apical

sterniterufous castaneaeRohwer,p.447.

DIMORPHOPTERYX

ABNORMISRohwer.

DwiorphopleryxabriormisRohwer,Proc. LI.S. Nat. Mus.,vol. 41, 1911, p. 406.

Thisspeciesis

remarkable

inthe

convex

scutellum

and

thelossof

"thetransverseradius.

DIMORPHOPTERYX MELANOGNATHUS

Rohwer.

Dimorphopteryx melanognathusRohwer, Proc.U.S.Nat.Mus.,vol. 39, 1910, p.205;

vol. 41,1911, p.405.

The

description of this species, dealingwith the clypeus,

may be

elaboratedas follows:

Clypeus

deeply, arcuately emarginate, almost subangular; lobes broadly triangular; supraclypeal areaflatexcept a small

rounded median

tubercule.

DIMORPHOPTERYX

ERRANSRohwer.

Strongylogaster pinguisDyar,Trans.Amer.Ent.Soc, vol. 22,1895, p.311;Journ.

N.Y. Ent. Soc,vol. 5, 1897, p.199 probably.

Parasioblarii/ocinctusHoward,InsectBook,1904, pi. 14,fig.26.

DimorphopteryxpinguiserransRohwer,Proc.U.S.Nat.Mus.,vol. 41, 1911, p.406.

As

faras I

am

able to ascertain

from

the

pubUshed

recordsthe host plantsof this species areblack oak,birch,

and

linden. It

may be

that inDyar'srearing

he had more

than

one

species included.

As

far as recentrearingsare available

no

species

has more

than

one

hostplant,

and

allthe larvaebelongingto this

genus

are so similar superficially thatfielddeterminations ordeterminations

not based on

adults

can not be

reliedupon.

Thisspeciesis

known from New York

State only.

DIMORPHOPTERYX

VIRGINICARohwer.

DimorphopteryxpinguisvirginicaRohwer,Proc.U.S.Nat. Mus.,vol. 41, 1911, p. 406.

This

may be

consideredas a

good

species.

The

following characters will aid in the identification.

Lobes

of the clypeus

about

twice as

NO.2181.

8AWFLIES OF GENUS DIMORPHOPTERYX—ROHWER. 447

longasthebasalwidth,their apices,obtuselytriangular; fouranterior

femora

yellowishorreddish; transverse radius received

basad

ofthe

middle

ofthecell.

DIMORPHOPTERYX

PINGUIS(Norton).

Allantus pinguisNorton,BostonJourn. Nat.Hist., vol.7,pt.2,1860, p. 244.

StrongylogasterpinguisNorton, Catalogue,p. 150.

DimorphopteryxpinguisAshmead,Can. Ent.,vol. 30, 1898, p. 308.

—

Rohwer, Proc.

U.S.Nat. Mus.,vol. 41, 1911, p. 405.

The

type-specimen of this speciesis lost,

but

a

neotype

isin the

United

States National

Museum.

MacGillivray^{^} says that Provancher's Sciapteryx

punctum

is the female of this species. I

have

not

examined

the

Provancher

type,

but

accept the

synonymy. Some

of

Doctor

Dyar's rearings

may

refer to this species,

but some

of

them

referto errans. If allother of

Doctor

Dyar'srearings refer to errans,the host plants of pinguis areAmelanchier canadensis

and

Maple.

DIMORPHOPTERYX

AUTUMNALIS,newspecies.

Female.

—

Length,8

mm. Labrum

broadly

rounded

apically;clypeus gentlyconvex, sparsely punctured, theapical

margin subsquarelyemar-

ginate, thelobes rectangular,

about

one-third as

wide

as the

width

oftheemargination; supraclypeal areaflat; arealatrad oftheocelli, postocellar area

and

posterior orbits, sliining, practically

impunc-

tate;ocellarbasin

with broad

slopingwalls,distinct

furrow from

the anterior ocellus tothe ventral

margin

ofthebasin; postocellar

furrow

straight; tliird antennaljointone-third longer

than

the fourth; scu-

tum and prescutum

sculpturedsimilarly;punctures ofthe scutellum large;sheath

with

dorsal

margin

straight,apical

margin sub

truncate, lower angle broadly rounded. Black; labrum,

apex

of theclypeus, posterior lateral

margin

of the

pronotum,

tegulae, scutellum, four anterior legs

below

the middle, the coxae,

most

of the posterior coxae, posterior trochanters

and

posterior tarsi,

wMte;

(the four anterior

femora

are slightly reddish);

abdomen beyond

the basal plates, posterior

femora and

tibiae

and

the antennae, castaneus;

wings

hyaline, iridescent, venation

dark brown

except the costa,

which

is reddish.

Falls Church, Virginia. Described

from two

females recorded

imder Bureau

of

Entomology Number Hopk. U.

S. 10168, material collected

by

C. T.

Greene and

reared

by William

Middleton.

Type-specimen.—

Cat.

No.

18189,

U.S.N.M.

DIMORPHOPTERYX

CASTANEAE,newspecies.

Female.

— ^Length,

⁸

mm. Labrum

long,broadly

rounded

apically;

clypeus evenly convex, shining, with scattered, large, well-defined punctures, the apical

margin

subsquarely emarginate, the lobes rec-

1Can.Ent., vol.40,1908, p. 368.

448 PROCEEDINGS OF TEE NATIONAL MUSEUM.

vol. 48.

tangular,

about

half as

broad

asthe emargination;supraclypeal area flat; ocellar basin well defined

by broad rounded

walls sloping in- wardly, elongate

and

confluent

with

the

middle

fovea,

but

deepest

immediately

infront of theocellus;area latrad oftheantennalfur-

rows

shining

with

widely scattered punctures; thepostocellar

furrow weU

defined,shghtly

curved

anteriorly; postocellararea

about

one- fifth wdder posteriorly, well defined; third antennal joint one-tliird longer

than

thefourth;sculptureofthethorax normal; sheathstraight above, subtruncate apically,

with

the lower angle rounded. Black;

labrum, tegulae, scutellum, apices of coxae, trochanters, four an- terior tibiae

and

tarsi, posterior tarsiwhitish;

abdomen beyond

the basal

segments

except the sheath, the posterior

femora and

tibiae except the

apex

of thelatter, castaneus;

wings

hyaline, iridescent, venation

dark brown.

Male.

— ^Length,

⁷

^mm. Labrum

^obtusely

rounded

apically, cly-

peus

flatas inthefemale;

head and

thoraxas inthe female;

hypopyg- ium

broadly

rounded

apicaUy. Colored as thefemale except the scutellumisblack; the apicesoftheposterior tibiae arehardlyblack.

Falls

Church,

Virginia. Described

from two

females

and

three males recorded

under Bureau

of

Entomology Number Hopk. U.

S.

10157e,_{/, g, h.} Materialcollected

and

reared

by W. Middleton and

the author.

Type-specimen.—

C&t.

No.

18187,

U.S.N.M.

DIMORPHOPTERYX

QUERCrVORA,newspecies.

Male.

— ^Length,

⁷

mm. Labrum

strongly

convex

basaUy, apical

margin

subtruncate; clypeus gently convex, broadly subsquarely emarginate, lobes rectangular,

about

one-thirdas

wide

asthe

emar-

gination; supraclypeal area gently

convex;

ocellar basin rather

weU

defined

by broad low

walls,partly separated

from

the

middle

fovea;

if the separation

were complete

it

would be

trapezoidal; the area latrad of the ocelH, the posterior orbits, the postocellar area with large, well-defined, scattered punctures; antennal furrows complete;

postocellar furrow well defined; flagellum flat, second joint

two-

thirds the length of the first;

scutum

with punctures rather

more

dense

than on

the

prescutum;

punctures of the scutellum large;

hyj3opygium

broadly

rounded

apically. Black; labrum, anterior

margin

of clypeus, tegulae,spot

on

the scutellum, fouranterior legs

below

theapices ofthe coxae,apices oftheposteriorcoxae,trochan- ters yellowish white;

abdomen beyond

^{basalplates, posterior}

femora and

tibiaecastaneus;posteriortarsi,except the base^ofthefirstjoint, pale ferruginous;

wings hyaUne,

iridescent, venation black.

Tomahawk Lake,

Wisconsin. Described

from one male

recorded

under Bureau

of

Entomology Number Hopk. U.

S. 10171, material collected

by

S. A.

Rohwer and

reared

by WilUam

Middleton.

Type-specimen.—

C&t.

No.

18188,

U.S.N.M.