LIMNOBINA. 51

Section

I.

LIMNOBINA.

One submarginalcell; four posteriorcells. Normal

number

ofantennal jointsfourteen(sometimes apparently fifteen). Eyes glabrous. Tibi.ne

without spurs at the ^tip. Ungueswith moreorless distinct teethon theunderside. Empodiaindistinctornone.

The group

thus characterized is natural

and

compact. It comprises

about

one-fourth of the

known

brevipalpous

Tipulidx

of the

United

States (35 species

among

135),

and

it

seems

that in

'Europe

nearly the

same

proportion obtains (in Austria 31 species

among

127, according to Dr. Schiner's enumeration).

The

forms of this section, belonging tothe temperate regions of

Europe and America (and

hardly

anything

is

known

about the species

from warmer

climates) affordbut littlestructural diversity

and

their relationship isso great

and

evident thatone is almost

more tempted

to unite

them

all in one

genus

than to subdivide

them

in several.

The Limnobina,

together with the

Limnophilina,

constituted thebulk of the

genus Limnobia

in

Meigen's

sense.

These two

groups

also very nearly correspond to the first subdivision of

Meigen's genus by Macquart,

in

Limnobia Macq. and Limno-

phila

Macq.

Thus, w^e

may

look

upon

these

two groups

as the repi'esentative ones of the brevipalpous Tipulidse. It

was

the greatsimilitude of their

outward

appearance,

more

than anything else,

which

causedthe speciesbelongingto

them

toremain united togetherin the

same genus from Meigen's

time

up

tothat of the latest publications,

whereas genera

like Rhipidia,

Rhamphidia,

Eriojitera,

Anisomera,

Pedicia, etc.,

were

singled out

and

sepa- rated quite early, not

on

account of

any

real

knowledge

of the peculiarities of their organization, but

merely

on the

ground

of

some

one conspicuous character distinguishing them.

And

yei, thecontrast of characters, presented

by

the

Limnobina and

the

Limnophilina

is very great

and

extendsto almost every portion

62 DIPTERA

OF

NORTH AMERICA. [part

IV of their organization,

ing;

two columns

^:

—

This contrast is expressed inthe follow.

Limnohina, Epistomalongerthan broad.

Flabsoflabiumlinear,narrow.

Antennre14-jointed.

Onesubmarginalcell.

Auxiliaryveinoften short, itstip being thenanteriortothe innerend of thesubmarginalcell.

The great cross-vein is almost alwaysat the innerendof the discal cell,orbeforeit.

Fourposteriorcells.

Tibiae without spursatthetip.

Unguesdentate ontheunderside.

Erapodiaindistinct ornone.

A

horny, elongated, immovable style on the under side of the forceps,inthemale.

Upper valves of the ovipositor often very short (especially in the genus Dicranomyia).

Limnophilina.

Epistoma generally transverse (broader thanlong).

Flabsoflabiumbroadandfleshy.

Antennae16-jointed.

Two

submarginal cells.

Auxiliary vein generally long,its tipbeingalmostalways nearly oppo- sitetheinnerendofthesubmarginal

cell.

The great cross-veinisveryoften opposite the middle of the discal cell.

Five (seldomfour) posteriorcells.

Tibiaewithspurs.

Unguessmooth.

Empodia

distinct.

Ko

horny,immovablestyleonth&

underside of the forceps.

Upper valves of the ovipositor generallylong.

The

teeth

on

the

under

side of the

ungues

of the

Limnohina seem

to

be

peculiartothis section.

They must

not be

confounded

withthe

more

orless squareorsharpprojection

on

the

under

side atthe very basis of the ungues,

forming

a part of thethickening

which always

exists there.

The

tooth of the

Limnohina, even when

single, isdistinct

from

this thickening,

and

placedbefore it

(outside of the

Limnohina, Antocha

is the only

genus which seems

to

have something

like thistooth).

The

style

on

the

under

side of the

male

forceps is also peculiar to this

group

; I

have observed something

analogoustoitonly

among

the Tijy.

anomalse

{Dicranoptycha, Antocha).

The North American and European Limnohina,

as far as

known, may

be divided in

two

natural groups,

one

of

which

has, in

most

cases, a short auxiliary vein, the marginal cross-vein

always

atthe very tipofthe firstlongitudinal vein,

and

the

male

forceps

formed

of

two

fleshy lobes

{Dicranomyia,

Rhipidia,

Geranomyia)

; theother

group

has, with rare exceptions, along

DICRANOMYIA.

53 auxiliaryvein,the marginal cross-vein is

sometimes

atthe tip, but

more

often at

some

distance

from

the tip of the first longitudinal vein,

and

themaleforceps consists of

two horny hooks {Limnohia,

Trochobola). Little is

known

about the forms of

Limnohina

peculiar to the tropicalregions

and

foreign to

Europe and

Nortli

America. The

Berlin

Museum

possesses several species

from Mexico and

Brazil, with a

supernumerary

cross-vein in the sub-

marginal

cell; the auxiliarycross-vein hasits tipnearly opposite theorigin ofthesecond longitudinal vein; the

ungues have

strong

and

distinct teeth; the

wings

are spotted.

These

species will

form

a distinct genus.* Another, still

more

aberrant form from

South America,

is represented

by

several species in the

same museum. In Mr.

Bellardi's collection, in Turin, I

have

seen a species

from

the PhilippineIslands,

remarkable

forits coloring_; it isblack, with

smoky wings

; thethorax is orange red.

As

farasIcan

judge

fromthe description ofthe

genus Periphe-

roptera Schiner₍Verh.Zool. Bot. Ges. etc. 1866,p. 933,

and

Beise

d.

Novara,

etc. Diptera,p. 47),it isonlya

form

of

Dicranomyia

;

thegeneric character willbe

found

in the Ap)p)endixII.

Geu. ^I.

DICRAIVOMYIA.

One snbmarginalcell; four posteriorcells;discal cellpresent orabsent

;

marginal cross-vein at the tipof the first longitudinal vein; tip of the auxiliaryvein generally opposite or before the originof thesecondlongi- tudinal vein,seldombeyond it(wingsofDicranomi/ice,Tab. I,fig. 1, 2,3).

Antennae14-jointed, joints subglobular,elliptical,orshort subcylindrical.

Proboscis notlongerthanthehead. Feetslender,tibisewithout spurs at thetip; empodiaindistinct ornone. The forceps of the maleconsistsof

twomovable,soft,fleshy,subreniformlobesandahornystyleunderthem (Tab.Ill, fig.2, 3, 5).

Rostrum

subcylindrical, projecting; epistoraa longer than broad,

narrowed

at the sides; the narrow, linear, pubescent flabs of the

under

lip project

more

or less

beyond

it. In

D.

rostrifera,rostrum

and

proboscis are nearlyas longas theliead

;

usually, hovrever, they are shorter_; palpi short.

Eyes

large, glabrous, front rather narrow.

The

antenna? are comparatively short,as they

do

not reach the root of the wings,

when

bent back-

wards

; the joints of the flagellum are subglobularor elH))tical

;

' LuniwbiadivaSchiner(Rcised.Novara,Diptera, p.-IG),fromBrazil,is

apparentlya species of thiskind.