152 DIPTERA OF NORTH AMERICA. [PART IV.'

ERIOPTERA. 153 veiu, are not inonelinewiththesmallcross-vein,tut

much

nearer to therootofthewing (Tab.I,fig.19): subgenus Molophilus.

The

peculiarities of the venation of this

group

are: 1.

That

the second longitudinal vein emits the third, not

from

its

main

stem, as usual, but from its posterior branch (as in

some

species of

Amalopis)

; hence thefirst submargiualcell is longer than the second; the latter, in all the species

which

I

have

seen, has its

inner

end

in one line with the inner

end

of the first posterior cell, both inner ends being nearly square; thefirst submargiual cell has usually a

somewhat rounded

innerend,

and

the marginal cross-vein isbut a short distance

beyond

it; in

E. ursina

nearly in

one

line with it; 2.

That

the first bifurcation of the fourth longitudinal vein takes place at a considerable distance before thesmall cross-vein,

and

that the great cross-veinisalso

removed backwards

to acorresponding distance; the consequence is, that the innerends &f thesecond

and

fourth posteriorcellsare nearer tothe basis of the

wing

thanthe inner ends of the firstposterior

and

ofthesubmargfnal cells.

The

djscalcell seemsto

be always open

(this is the case with the

North American

species, as well as with the

European

species,

which

I find

mentioned

in the authors).

The

third posteriorcell isratherlongin

most

species,

and

has its inner

end more

or less opposite that of the first posteriorcell; inE. ursina,

however {and

pr51>ablyin the related

European

species), itis

much

shorter.

Dr. Schinerhasi-etained the

name

of

Erioptera

forthis sub- division,butthis

name

is

more

properly appliedtoanother group.

As

Molophilus, a generic

name

pi'oposed

by Mr.

Curtis for a species of this

group

with very short wings, unfit for flying,

cannot

well be retained in this

narrow

sense,

we may

applyit to thewhole group.

Table fordeterminingthespecies.

/The

prwfurca ends in thesecondsubmargiualcell (Tab.1, fig. 16, 17,

l]

18). 2

ITheprffifurca endsinthefirst submargiualcell(Tab. I, fig.19). 13 The discal cell,

when

open, coalesces with the second posterior cell (Tab.I,fig.16);

when

closed,the innerendsofthe second and third posteriorcellsarenotinoneline,the innerendofthelatter being anterior(Tab. I, fig.17,18). 3 The discal cell,

when

open, coalesces with the third posterior cell; I

when

closed, the inner ends of the second and third posterior

»• cellsarenearlyinoueline. 12

154

DirTERA

OF

NORTH AMERICA, [PART

IV.

'Discalcell open; seventli longitudinalvein arcuatedinsuch aman- nerthatthe axillarycell is broaderinthemiddle than nearthe

margin (Tab.I,fig.16). 4

Discalcellclosed; seventhlongitudinal vein straight,divergingfrom the sixth, and, hence, the axillary cell

much

broader near the marginthaninthemiddle (Tab. I,fig. 17,18). 9

Knobof the halteres jellow. 5

Knobofthe halteres iufuscated. 1septemtrionis0. S.

^ )Body andwings yellow^orgreen. 6

(Body andwings brown. 2villosa0. S.

^Cross-veins not infuscated,feet yellow. 7

6<Cross-veins infuscated,feetconspicuously clothedwith blackhairs.

' 3

chrysocoma

0. S.

(K

Front and humeriwith sulphur yellow marks, theremainder ofthe headandofthethorax beingofasaturated reddishorbrownish- f

7-1

I yellow. 4 vespertina0. S.

^Whole bodypalegreenorpale yellow. 8

„(Bodypale green. 5 chlorophylla0, S.

\Bodypale yellow. (5straminea, n. sp.

fNo

stump of a vein inside of the discal cell; femora with brown

bands. 10

A

stumpof a vein inside of the discal cell (Tab.I,fig. 18); femora

withoutbrownbands. 10

armata

0. S.

rWingswith a broad brown band and a large brown spot before it,

,^_j nearerthe basis (Tab. I, fig. 17). 7

venusta

S.

j Wings with a very narrow brown band and numerous brown spots

^ andmarks. 11

rPrevailing color of thebody andof thewingsyellowish.

-.-. I 8armillaris, n. sp.

I Prevailing color of thebody andof thewings brownish.

^ 9graphica0. S.

^Wingsbrownish, withnumerouswhitespots. 11caloptera Sny.

12< Wingspale grayish,with small dark spots along themargin,at the

' tipof the longitudinal veins. 12

parva

0. S.

,o (Prevailing color of the bodyyellow. 13pubipennis0. S.

iPrevailing colorof thebody brownor black. 14

,- (Size from0.2to0.25; colorbrown, 15

(Sizehardly0.1; colorblack. 16 ursina0. S.

,g ⁽Antennaealtogetherbrownish, 14 hirtipennis 0.S.

(

Two

basal jointsofthe antennae yellowish. 15forcipula, n. sp.

ERIOPTERA. 155

Description ofthespecies.

A. The praefurca ends in the second submarginal cell, which is longer than the first; the inner end ofthe discal cell (or,

when

it is open,ofthecellwithwhichitcoalesces)isonthesamelinewith thesmallcross-vein.

1. Theposteriorbranchof the fourth longitudinal veinisforked.

a. Seventhlongitudinal vein arcuated,converging towardsthe sixth(Tab.I,fig.16)^: subgenusErioptera(compare above,page151).

1.

E. septemtrionis

0. S. % and

9.—

Fuscano-ochracea,alisim- maculatis, venarumvillosieperbrevi, halteres capitulo infuscato.

Brownish-ochraceous, wingsimmaculate,thepubescenceoftheveinsvery short, theknob ofthe halteres brown. Long. corp.0.2

—

0.25.

Syn. Erioptera septemtrionis 0.Sacken,Proc.Ac. Nat.Sc.Phil. 1859,p.226.

Body

ochraceous,

more

or less tinged with brownish; front infuscated inthe

middle

_; palpi

brown

_; antenna3 brownish,

more

or less pale at the basis; thorax

brownish

above, with

more

or lesssulphur yellow inthe

humeral

region; a

brown

stripe,

more

or less distinct, along the

middle

of the

mesonotum and

of the collare_; pleurae usually pale,

with

a

brown

stripe, running

from

the collare to the root of the halteres; in

some

specimens, the pleuriB are brownish;

knob

of the halteres

dark brown

; feet brownish-yellow;

abdomen brownish

above, venterpaler.

Wings immaculate

; veins brownish, their pubescence very short, not long

enough by

fartoreach

from

vein tovein

and

thus to cover the surface of the cells.

Hab. Maine

(Packard);

Sharon

Springs,

N. Y.

;

seems

to

be more common

inthe north. I possess a

male from Washington, D. C, which

is altogether brownish,

humeri

yellowish, forceps T-eddish; a female of very large size (localityuncertain) has the

same

dark coloring. I believe that they belong to

E.

septem- trionis,

which

can always be distinguished

by

the

dark knob

of the halteres

and

the short pubescence of thewiugs.

2.

E. Tillosa

0.S. %^.

—

^Fusca,alisfuscescentibus,oonspicuefusco- villosulis,halteribusflavis.

Brown,wings brownish, with conspicuous brown hairs; halteres yellow.

Long. Corp. 0.25.

Syn. Eriopteravillosa0. Sacken,Proc.

Ac

Nat.

Sc

Phil. 1859,p.226