514 PROCEEDINGS OF THE NATIONAL MUSEUM

The

followingis a description ofthe color of thoreyi:

Male.—h&hTum

luteoiis,edged above and below with black, that above connecting with acircularmedian spoton the center of the

Figs. 126-129.—Tantpteryxhageni, wings.

Figs.130-132.—Tachopteryxthoreyi, wings.

labrum. Nasus black. Frons yellow, except the posterior edge of Its horizontal surface which is edged with black. Vertex black.

NO. 2192.

DRAG0NFLIE8, CALIFORNIA AND NEVADA— KENNEDY.

₅₁₅ Occiput yellowwitha black

band

alongitsposterior edge. Posterior surface ofhead black. (Seefig. 115.)

Prothorax black, its anterior and posterior lobes yellow. Proin- fraepisternumpale.

Mesothorax and metathorax oHve

brown

with dark bro\vn, ob- scurely edged markings. Middorsal carina black. All alar ridges black,

A

^broad

band

on humeral suture,a similar broad

band

on secondlateral suture, and a third on the metasternal keelbrown.

Infraepisterna yellow. All coxae and legs black.

Abdomen

with segment1 pale.

Segment2yellow,withfourdorsalblack spotsand a spotoneach side posterior totheauricle.

Segment 3 yellow,with thelower edgeof the side black and two tandem, lozenge-shaped, black spots onthe middorsal line.

Segments 4 and 5 similar to 3 but with theposterior of the two

doi-sal spotsexpanded into a quadrilateralspot covering the entire dorsumposterior totheverticalcarinaeexcept anarrow

band

across the apexofthe segment.

Segments6and 7 similar to4and5 exceptinthe greaterextentof the post-dorsal spotwhichconnectsatitsapex oneachsidewiththe blackoftheloweredgeofthe segment.

Segment

8 black except for a rowof three small yellow spotson theupperpartofeachside.

Segment

9with anirregularanterodorsalspot.

Segment 10and appendagesblack.

Female.—Colored as the male but theblack sUghtly

more

exten- sive (seefig. 116).

The

upper endofthe mesinfraepisternumblack.

The

anterioredge and

dorsum

ofsegment 1 dark.

The

fourdorsalspotson segment2 and the lateral spot of the

same

segment larger.

The

postdorsal spotinsegments3 to 7 covering the entiredorsum posterior to the vertical carinae.

Segment

9 aswellas 10 entirelyblack.

Measurements: Male

abdomen

(incl. appendages), 55

mm.;

hind wing,50. Female abdomen,57

mm.;

hindwing,^50.

Structurally this species is pecuUar in lacking the metathoracic tubercle foundin Tajiypteryx. In themale the superior appendage has aminute toothonthemiddleofits inferior edge.

The

inferior appendageiswithoutamediantenninal lobeandhas apair ofsupe- riorbasal hooks. In the female thestylus isplacedsubapicaUy on thegenital valve. (Seefigs. 117-120.)

8.

NOTES ON CORDULEGASTER DORSALIS AND

C.

DIADEMA.

The

ninespecies of Cordulegaster

known

from North America are recorded from mountainous regions, though two are found also in the hiUier areas of the northern Mississippi VaUey. Six of these speciesoccurⁱⁿthe Appalachians.

Two

arefoundinthemountains

516 PROCEEDINGS OF THE NATIONAL MUSEUM.

vol.52.

of the Pacific slope while one other is recorded so far only from Mexico and Central America.

The

western species are C. dorsalis

Hagen

andC.diademaSelys. Dorsalisoccursinthe coastmountains from Sitka,Alaska,southto theSanGabriel Mountains atLos

An-

geles,California. Itisfound

up

toanelevationof4,000feetonthe west slope of theSierras in California buthas never beenrecorded fromthe easternside ofthesemountains.

Diadema

isrecordedfrom the mountains of Arizona and northern Mexico.

My

recordsfor Cordulegaster dorsalis are as follows: Stevens Creek, Santa Clara County, California,

May

31, a single fresh exuvia and several grown

nymphs

were collected but no imagoes were seen;

July 7, eightmales were observed; August 16, threemales and one female were caught, the latter while ovipositing. Zyante Creek, Santa Cruz County, Cahfomia,July9,numerousexuviaewerefound but no adults were seen.

Napa Asylum

Grounds,

Napa

County, Cahfornia,June8-9, sixmalesweretakenonasmallmountain stream flowingfrom the Hospitalreservoir; nofemales wereseen. In Mr.

FordyceGrinnell, jr.'s,collectionisamaletakenontheArroyo Seco atPasadena,California,June 29, 1910.

The

follomngrecords arefrom thewest slope ofthe

main

Sierra Chain:

On

theAmerican RiveratAuburn,PlacerCounty,California, July20, a singlemale wasseen repeatedly at closerangewhich

had

probablystrayedfrom one ofthesmall spring-fedsidestreams. In Bear Valley at Emigrant Gap, Placer County, Cahfornia, a single malewas taken July21; two otherswereseen. Thiswas atanele- vation of 4,000feet, the highest elevation at which this species is

recorded, andisalsothemosteasternrecord, thoughitis stillonthe westslope oftheSierras.

Much

that I shall write concerning Cordulegaster dorsalis wiU be almost a repetition of that concerning Octogomphus, as the habits anddistribution of these in California are in

many ways

similar.

As

far as I have observed, C. dorsalis is found usuallyon those swift mountain torrents which do not freeze in the winter time.

There

may

beexceptionsto this,as Itookthisspecies at an eleva- tion of 4,000feet in BearValley (Emigrant Gap, Cahfornia), where there is a heavy \\dnter snowfall and probably the streamsfreeze, though

many

of them are fed

by numerous

springs which

may

moderatetheirtemperature. In theCoastMountainsof Cahfornia, whereitappearstoreachitsgreatestnumbers,it isfoundintheswift upper reaches of all the perennial streams. Here it is associated with Octogomphus specularis, AesJinawalkeri,^ and Argia vivida, the last breedingin the springs of themountain gorges. I have never seenortakenCordulegaster,exceptinthe steepcanyonsofthe

moun-

tains. Itdoes not occuronthe lower reaches ofthese

same

streams aftertheyhaveemergedonto thelevelvalleyfloorsand havelosttheir

»See pages588-592.

NO. 2192.

DRAG0NFLIE8, CALIFORNIA AND NEVADA— KENNEDY.

517 swiftness to become

warm

and

muddy.

In the steep and narrow mountaingorgeswherethe rushingtorrents pour

down

through the shadeoftheredwoods andalders, thisdragonfly adds a note of mys- tery to the scene, for the individuals with their strange ophidian coloration gUde noiselessly

up

streamor down, nevershowingthat curiositytowardstrangersorunusualsurroundingswhichisexhibited

by

the libeUuhnesof the sunnyvalleys,but always

moving

straight aheadasthoughdi-awnirresistiblyonward. Onlymalesare

common

on the streams, the femalesseldom resorting tothewaterexceptto oviposit.

The

males, asindicated above, flyonthelongestbeats I haveobservedforanydragonfly, fortheyflycontinuously

up

stream or

down

untilthey

come

totheheadofthestreamor totheslowwater below, oruntil

some

unusualobstruction turns

them

aside,

when

they faceabout andflyassteadily intheopposite direction.

The

course

isusually afoot ortwo above the surface of the stream and goes throughdenseshade and anyloosebrush orfoliagewhich

may

hang over the water. OctogompJius,withthepossibleexceptionofAeshna

walJceri, is the only other western dragonfly which wiU flyin such close darkplaces. Becauseof thishabit of flying inlong beatsthis dragonflyisnoteasilytaken,asthecollector hasbutasinglechance ateachindividual.

Ihaveseenbutone female over the water. This onew^as oviposit- ing. Ihave seentwo otherswliich I thought were females on the mountain sideseveral hundred feet above the stream.

As

I have seen

many

malesonthestreamsandonly thesinglefemale,Iconclude that theseseldomresorttothewaterexceptto oviposit.

InthestreamsoftheCoastMountainsof California, v>^hereIhave

had

opportunitytoobserve the habitsof Cordulegastermost,itshows a

marked

upstreammigrationofthe imagoes.

The

eggsare laid inthe shallowwateralong the edgesofthestreamandthe

nymphs wander

aimlesslyover the bed. Becausethe

nymphs

are free onthestream bottom each freshet dm-ing the threeorfour years of

nymphal

life serves to

wash them

fartherdowTistream sothat

when

they

come

to emerge they

may

befardownstream from the placewhere the eggs weredeposited.

On

Stevens Creek (Santa Clara County, California) exuviaewereabundantalmost

down

totheTrout Farm,whilefew ima- goeswereseen below Soda Spring,which is 2 miles farther

up

the creek, and imagoes were

common

on thedivide at theheadof the creek,where fewexuviaewerefound. Exuviae were abundant onthe lower part of Zyante Creek (SantaCruz County,CaHfornia),where noadultswereseen,thoughitwasat the heightof theCordulegaster season.

From

the above andsimilar observations on Octogomplius, I have concluded that the imagoes

show

such a preferencefor the swifterwateroftheupperreaches ofthesestreams that

when

they reach theupperpartof thestream in theirfirst flightstheyremain