two fossil insects from florissant, colorado

TWO FOSSIL INSECTS FROM FLORISSANT, COLORADO, WITH A DISCUSSION OF THE VENATION OF THE AESHNINE DRAGON-FLIES.

By

T.

D. A. COCKERELL,

0/^{the University}ofColorado,Boulder.

The

Florissant shales

continue

to yield

important new

materials for the

study

of Tertiary insect life.

The specimens now

discussed are of special interest

because

of their relation to certain

modern

forms,

and

in

one

casethe investigation

has been extended

toinclude thevenational characters of the aUied

modern

genera.

Order ODONATA.

Fanuly AESHNID^.

OPLON^SCHNA

LAPIDARIACockerellandCounts,newspecies.'

Hind wing

of

male;

length

about

42

mm.; hyaUne, venation

piceous;

stigma dark

piceous;

stigma

5

mm.

long,

bounding _{3| long}

cells

below;

triangle of five cells,

two

basal, the

formula

2, 1, 1, 1;

branches

of

media

leaving arculus considerably

below middle; M3 and M4

at

margin

of

wing separated by two

cells,

M4 and

the supple-

ment

also separated

by two

(one only in 0. armata);

M4 without any

evident deflection or bulging

about

six cells

from margin

(such a bulging

very

distinct in 0. armata)',

Rs unbranched, separated from

the

supplement below

it

by about

five

rows

of cells at

widest

part (three orfour in0. armata).

Compared with

the

hving

0. armata, the

stigma

is

much

longer,

and

ⁱⁿ the

type-spe6imen has

a cross vein (Mr.

E. B. WiUiamson

thinks this is a freak,

but

that

such

freaks are

probably

confined to species

with

a

long

stigma.

Needham's

figure of Tachopteryx,

which has an

excessively long stigma,

appears

to

show

a cross vein); the cell

beyond

the

stigma

is

not

nearly twice aslong as the

next

follow- ing one; the origin of the

branches

of the

media from

the arculus is

1Thisspecieswasfirststudiedanddrawn byMissHildaCounts,whoseworkhasbeenincorporated in thispaper.

ProceedingsU.S.National Museum,Vou.

45—

No.2000.

80459°—Pi'oc.N.M.vol.45—13 37 577

578 PROCEEDINGS OF THE NATIONAL MUSEUM.

^VOL.45.

quite different.

Compared with

tlie Florissant fossil 0. separata (Scudder), 0. lapidariais at

once separated by

the

low

origin of the

branches

of the

media from

the arculus,

which

iscertainly

not due

to distortion.

From

thelevel of the arculus to the

lower

cornerof the triangle there are three full cells,

whereas

0. separata

and

0.

armata show

only 2 to 2^.

The ends

of

Mg and M4 and

the

supplement

agree

remarkably

well

with

the

European

fossil 0. metis (Heer),

but

metis

has

the

branches

of the

media

arising

from even

a little

above

the

middle

of the arculus.

The

radial sector

and

its

supplement, with

the ceUs

between,

are

more

like those of 0. metis

than

those of the living 0. armata.

Locality.

— Miocene

shales of Florissant, Colorado, Station 13

B, University

of

Colorado Expedition;

collected

by

S.

A. Rohwer.

Cotypes.

—Cat. No.

59922,

U.S.N.M.

Fig.1.—OPLONiESCHNALAPIDAEIA. O,STIGMA;b,TEUNGLE ANDARCULUS; C,ENDSOF VEINS M3ANDM^;

d,EADIALSECTOKANDSUPPLEMENT.

This specimen puzzled us much, on account

of the peculiar origin of the

branches

of the

media from

the arculus,

a

condition

not found

in the allied species or genera.

There

are genera, as Planseschna

(fig. 2, h, c), in

which

the origin is

below

the middle,

but

these are otherwise quite different; as this character

shows no

evidence of

being abnormal

in

any way, we can only regard

the

wing

as repre- senting a

new

species.

I consulted

Mr. E. B. Williamson on some

ofthe characters of tliis

species,

and he was

so

kind

as to

loan me

a

very

fine series of

photo-

graphs

of various

Aeshnine

genera.

Using

these

with

other materials

abeady

in

my

possession, I

have made

a

key

to the principal

genera

of Aeshninse,

based on

the venation.

This

is

given

below,

and

it is

hoped

thatit ^vill

be

of service in

determining

fossils,

which

areusually represented

only by

the wings.

An

effort

has been made

NO. 2000.

TWO FOSSIL INSECTS— COCKERELL. 579

to cite truly generic characters as far as possible,

but

the specific

names

are usually given,to

show what

species

were used

inthe study.

In some

cases other species

were

available,

but were not

included, as

they introduced no important

additional characters.

Fig.2.—a, Oplon^schna separata (ScunrEPO, trianglesfrom two specimens COLLECTED ATSTATION14,FLORISSANT; 6,PLAN^SCHNAMULTIPUNCTATA, TRIAN- GLE OF HIND wing; C,PlAN^SCHNAFORCIPATA,TRLVNGLE OF HIND-WXNG.

Itisgenerallyrecognized that

Oplonaeschna

is arelativelyprimitive

member

of the Aesbninse; it is thereforeinteresting to find it in the Tertiary rocks of

both America and Europe. Nevertheless

true

Aeshna,

of the

modern

type,

was

presentinthe

Miocene

of Florissant.

KEY

TO THE PRINCIPAL

GENERA

OF AESHNINJS, BASED ON THE VENATION.

(A) Basalspacewithoutcrossveins.

(a) Radialsectornotbranched; branchesofmedia leavingarculusatornearmiddle [belowmiddleinOplonaeschnalapidaria].

Radialsectorseparatedfrom supplementary veinbelowitbyonerowof cells 1 Radialsectorseparatedfromsupplementary veinbelowitbytwo towsofcells;triangle ofanteriorwings

much

longer andmore slender thanthatofhind (the latter only three-ceUed) Allopetalia reticulata [W^illiamsonphoto.].

Radialsectorseparatedfromsupplementary veinbelowitbythreerowsof cells fora considerable distance; triangles ofanteriorandposteriorwingsmore alike.. 3 Radial sector separated from supplementary vein below it by four rows of

cells Oplonaeschnametis(Heer).'

1. Anal loop of hind wings of three cells; triangle of three cells; [abdomen modi-

fied] Oligoaeschna[DolaeschnaNeedham].

Analloopofhind wingsofmorethanthreecells 2 2. Stigma bounding1^cellsbelow; anal loopof 4cells; triangle of 2cells.

Gomphaeschnafurcillata

.

Stigmabounding _{2 J cells} below; anal loopof 5 cells. (Miocene genus).

Lithaeschna.'^

3. Stigma narrow and elongate, bounding about 4J^cellsbelow; triangle of anterior

wings with three cells BasiaeschnaJanata.

Stigma

much

shorterand^deeper,bounding about2^^cellsbelow; triangle ofanterior

wings withsixcells Oplonaeschna armata.

1ThisisAeschnametisHeer,fossil atRadoboj. Handlirsch, followingHagen,refersittoAnax, but Heer'sfigureshowsthatthiscan notbecorrect. Thereference toOplonaeschna hasalreadybeenindicated by Needham. Ireachedthesameconclusion before noticingNeedham'sremarks.

2ThecharactersofIdtliaeschnaaresetforthatlength,andcontrastedviththoseofGomphaeschna,etc., in Bull.Amer. Mus.Nat.Hist., vol. 23, (1907)pp. 133-136. ThetriangleofLithacschnaisthree-celledby thedivisionofthe basalcell,as iaAllopetalia. Thegenusisperhapstooclose toGomphaeschna.

580 PROCEEDINGS OF THE NATIONAL MUSEUM.

^vol.45.

(b) Eadialsectorwithout a distinct branch, butivith

many

slender branch-likeveins arisingfrom its lower side; branches ofmedia leaving arculus near the top;

supplementaryveinbelow M^in hindloings withanextremely strong, almost S-like curve. (Tribe Anacini, new.)

Triangleof hind wings four-celled, the basal cell not double; Cugbentsothat the partbelowthetriangleisnearer thewing-margin thanthatjustbeyond.

Hemianaxephippigera [Williamsonphoto.].

Triangleofhind wingssix-celled,withtwobasal; Cu2notbentasinHemianax.

Anax

Junius.

(c) Radial^sectorbranched(forked).

Radialsectorseparatedfrom supplementary vein below ^it

by

only one row^ofcells;

triangleswith not morethan three or four cells 1

Radialsectorseparatedfrom supplementary vein below it

by

more than one row of

cells 4

1. Stigmalong,bounding about3^^cellsbelow 2

Stigmashort, bounding 2-2| cellsbelow; branches of

Cu

below triangle in hind wing separated

by

only one row of cells; branches of media leaving arculus

considerablybe^owitsmiddle 3

2 Branchesof

Cu

^{below triangle in hind wing separated by} only one row of cells (but threerows near marginofwing);triangles oftwocells..Brachytronpratense.

Branchesof

Cu

below^{triangle in}hindwingseparated in partbytwo rowsofcells;

triangleswith three or four cells Nasiaeschna pentacantha.

3. Trianglesnormally with three cells (sometimes a small fourth ceW). .Planaeschna fordpata[photo, of thisQueenslandspecies sent

by

^{R. Martin}toWilliamson].

Triangleswith only twocells Planseschna multipunctata [Williamson^photo.].

4. Triangles with eight cells; Rs separated from supplementary vein below it

by many

rows of cells (6 or 7in widest part); branches of

Cu

belowtriangle in hindwingseparated

by

two rowsofcells; arculusfarbasadof triangle; wings moreelongatedthaninGynacantha..Staurophlebiareticulata[Williamsonphoto.].

Triangleswithtlireeto sixcells 5

5. Not morethantwo rowsof cellsbetween

M4

and supplementary vein belowitin hind wing;triangleswithfivecells,the apicalone verylong; Rsseparatedfrom supplementary vein belowitby morethanonerowof cells (3 inwidestpart);

branchesof

Cu

belowtriangleinhindwingseparated inoneplace

by

two rows ofcells; arculusofanteriorwingnotmoreremote fromtrianglethanthe equi- valentofhalflengthofbaseoflatter Aeschnophlebiaanisoptera.

Morethantwo rowsof cellsbetween

M4

andsupplementary vein belowitinhind

wing 6

6. Forkof radial sectorbelow middleofstigma(oralittlebefore middle);triangles of fourcells,only onebasal; Rsseparatedfrom supplementary vein belowitby

4 or 5 cells atwidestpart Coryphxschnaingens.

Forkof radial sectorbeforelevel ofmiddleofstigma, nearlyalwaysbeforelevel of

beginningofstigma 7

7. Triangles inboth wings tliree celled,with only one basal cell; stigma longerand

narrowerthaninAe. cyanea 8

Triangleswith twobasalcells,or rarelyonly onein anteriorwing 9 8. Fork of radial sector considerably before level of stigma; branches of

Cu

below

triangleinhind wingsseparatedbytwo rowsofcells.

Aeshnabonariensis[Williamson photo.] female.

Fork of radial sector below beginning ofstigma; branches of Cu below triangle separatedbyonerowof cells(exceptone doublecell).

Aeshnasp.fromBrazil [Williamsonphoto.].

9. Triangles, at least in anteriorwings,oftixcells,a basalpair,andfoursimpleones

beyond ¹⁰

NO. 2000.

TWO FOSSIL INSECTS— COCKERELL. 581

Triangles withnot more than five cells, or

when

rarely with six, two pairs, the

formula2, 2,1, 1 11

10. Analloopofsevencells Gynacaniha trifida.

Analloopoftwelvecells GynacanthafromSiam[Williamsonphoto.].

11. M3 and M4 separated

by

one cell only at marginof wing, but a short distance before

by

^{two rows} of cells, owing to the deflection of M4 from the straight course; cellformulaoftriangles 2,1, 1; upper branchofradial sector inaline withstem; Rsseparatedfromsupplementary vein belowit

by

onlythreerows of cells; fork of Rsa shortdistance before level ofbeginning of stigma (sub- genus Hesperaeshna,

new

subgenus) Aeshnacalifornica.

Mg and M^separated

by

at leasttwocellsatmarginofwing,sothattheyarealmost orquiteas farapart hereasatanypartoftheircourse; triangleswithfivecells, at least in anteriorwings; Rsseparatedfromsupplementary vein belowit

by

fourrowsofcells, at least atwidest part(mainlythree rows,withfouronlyat

oneplate, inAe.solida) 12

12. Anal loop jnhind wings very large, with about 15 cells; stigmacomparatively

short Aeshnaq/anea[Williamsonphoto.].

Analloopinhind wingsnotso large 13

13. Branchesof

Cu

belowtriangleseparated

by

^asinglerowofcellsforthemostpart, but afew paired cells present, the

number

variable; upper branch ofradial sectormaking a strong anglewith the stem,butthelowerbranch nearly in a straight linewiththestem Aeshnasolida[fossilat Florissant].

Branches of

Cu

below triangle separated through most of their course

by

two

rowsof cells Aeshnaeremita.

Note on

Aeshna.

—

^I

am

unable to findanysatisfactorygeneric characters in the venation to separateAeshna from Gynacantha. Accordingto E. M. Walker's phylo- genetictree,GynacanthaisdeiivedfromAeshna. The numberof cellsinthetriangle in Aeshnavaries within specific limits, as wasfully shown in AmericanJournal of Science, vol. 26, 1908, p. 74. Walker, in his revision of North American Aeshna, findsthe following venational characters validforgroups:

Analtriangle ofmalesthree-celled 1

Anal triangle of males two-celled; females withfork of Rs decidedly asymmetrical

atbase Cserulea,junceaandclepsydragroups.

1. Females withfork ofRanearlysymmetricalatbase.

Californicaandmulticolor groups.

Females withfork ofRsdecidedly asymmetricalatbase Cyaneagroup.

Fora further discussionof Aeshnavenation see Entomological News, Dec, 1908, pp.^455-459.'

(B) Basalspacewithcross veins.

(a) Radialsectornotbranched; branches0/media leavingarculusatornearmiddle.

Radialsectorseparatedfrom supplementary vein belowit

by

two rowsofcells; stigma bounding more than three cells below; triangle of anteriorwings with tliree

cells Boyeriairene.

(b) Radialsectorbranched.

1Anelaboratetable,contrastingthevenationofAeshna, Coryphxschna,Episeschna,Planxschna,and Nasixschria,isgivenbyWilliamsoninEntomologicalNews,1903,pp.^5-7. Episeschnahas acuriously intermediate, or asitwere undecided,venation. Runin the tableabove,itgoes tothe vicinityofHes- perseshna,but withdifficulty,because(1)Rsisseparatedfrom supplementaryveinbelowitbyapartially doublerowofcells;triangleshavefive cells; (2) M4isseparatedfrom supplementaryveinbelowitin hindwing byonlyaboutthreetriplecells,therestbeingdouble;₍₃₎the triangleofhindwing has a simple basalcellinWilliamson'sfigure; (4)M3andM<areseparatedbyonecellatmarginofwing,but although thereissomedoublinghigherupinhind wing,Mtisnotdeflectedoutofitscourse. Williamsonstates that the basalcellof triangle inEpixschnaisdividedin front wing,andrarelydividedinhind wing. He

alsostatesthat the basalcellofthe triangleisveryrarelydividedinCoryphxschna.

582 PROCEEDINGS OF THE NATIONAL MUSEUM.

VOL.45.

Triangles with 8 or 10 cells; Mj strongly arched above fork of Rs; branches of

Cu

belowthetriangleinhindwingseparatedfora considerabledistance

by

three rowsofcells; branchesofmedialeaving arculusdistinctlyabove middle.

Neurseschnacostalis[Williamsonphoto.].

Triangleswith not more than 7 cells;

Mg

more gently and regularly arched above forkofRs; branchesof

Cu

belowthetriangleinhind wingsseparated

by

oneor

(Amphiaeschna)two rowsof cells 2

1. Stigma veryshort, bounding about2 cellsbelow; triangle ofthreecells,the basal onenot divided; branchesofmedialeaving arculus wellbelowitsmiddle.

Calixschna microstigma[Williamsonphoto.].

Stigmalonger, boundingat leastthreecells below; triangle of at least fivecells,

twobasal, at leastinhindwing 2

2. Branchesofmedialeaving arculusbelowthemiddle; only onerowof cellsbetween the Rs and supplementary vein below it; arculus close to base of triangle;

stigmamoreorlessswollen,bounding_5-5J^cellsbelow; adark patchatnodus.

Telephlebia godefroyi[Williamsonphoto.].

Branchesof medialeaving arculus abovethe middle;

many

rows of cells (about six atwidestpart) between Rs and supplementary vein belowit; arculusnot so close tobaseoftriangle^; stigmabounding3-3_{J cells}below 3 3. Branchesof

Cu

belowtriangleinhindwingseparatedbyonlyonerowofcells.

Amphiaeschna fromSiam[Williamsonphoto.].

BranchesofCu below trianglein hindwing separated

by

two rowsof cells fora considerable distance Amphiseschna ampla [Williamsonphoto.].

The Jiirassic Cymatophlehia and Morbseschna (see Bull. Amer. Mus. Nat. Hist., vol. 23, pp. 133-134, ^{141, 142)}are certainlytobe excluded fromthe Aeshninse.

On

other grounds, E. M. Walkerdivides the AeshniuiE into fivegroups.

One

of these correspondswith the Anaciniabove. Theothers

may

represent a

number

of tribes as follows:

NO. 2000.

TWO FOSSIL INSECTS— COCKERELL. 583

Order DIPTERA.

Family PHORID.E.

PARASPINIPHORA LAMINARUM

(Brues).

PhoralaminarumBrues, Bull.Amer. Mus. Nat. Hist., vol. 24, 1908,p.275.

This was

described

from

asingleimperfect

specimen. Three

others

have been fomid

at Florissant, allatstation 17,

two by Mrs.

Cockerell,

one by Mr.

S.

A. Rohwer. From

these I

have prepared

the

accom-

FiG.3.— Paraspiniphralaminarum. a,diagrammaticfigureof middle TIBU; 6,PART OFMIDDLETARSUS, SHOWING ARMATURE;C,PARTOF HIND TARSUS,SHOWING ARMATURE;d,SCUTELLUMANDADJACENTPARTS,SHOWIKQ bristles;e,endoffemale abdomen.

panying

figm-es,

which

explain themselves,

a

is

from one specimen;

6, ^c, d,

from

another; e,

from

the third. All

show

the character- istic

armatm*e

ofthe

hind

tibiae,

resembling

thatof the recent species

P.

multiseriata (Aldrich).

The modern

representative,

however, has only two

scutellar bristles insteadof fom-.

The new

materialof

P. laminarum shows

that thespecies

has

well-

developed

wings.

Plesiotype.—C&t.

No.

59923,

U.S.N.M.