LETTERS FROM THE SOUTHWEST.

376 ENTOMOLOGICAL SOCIETY

burst

upon

^{us in the}valley,

and

rainwithblastsof

wind

obscured the scenery.

I

went

^to _sleep ^for awhile,

and when

I

awoke,

^{behold theearth}

had grown

green with grass.

A

refreshing coolness succeeded the hot breath of the desert.

The

mountains

came

closer

and

the valley rose

between

them,

and

cultivated fieldsofalfalfa

began

^to appear. Finally, groves^of red-limbed fruittrees, with _shining threadsof_irrigation waters, linedour way,

and

at sunsetthe

cows came

_trooping

home

tothefarm yards

wading

knee deep^inclover.

This

was

the end of the desert

and

the

summit

of the divide at

Beaumont. Thence we

whirled

downwards

in the darkness, passing

towns

innumerable, with junctions^toPasadena, Redlands,

Pomona, and many

^{others, well}

^remembered

^names.

At

^last

we saw

the twinklinglights of a great city,

and

the various stations of

Los Angeles were

^called.

LETTERS FROM THE SOUTHWEST.

SaltonLakeinthe Colorado Desert andItsInsectFauna.

BY H.

G.

HUBBARD.

YUMA,

ARIZ.,

March

_{30, 1897.}

In regard ^to

what you

say of the ^insects collected by

me

in the desert

washes

^at

Palm

_Springs,thattheCalifornia desert

was

once an

arm

of the California_gulf,

you

are surely mistaken.

The

shells foundinallthisregion are^allfresh-waterremains;

and

themarine shells are found only ^{to the} south of the divide

which bounds

theSalton Sea.

The

desert sands bordering ^thisdepression ^are white withsmall _shells, but _{they are}all of the usual fresh-water forms. I havepreserved a

few

of the smaller

and most abundant

forms. I believe even from

my

^{short visit to Salton that I}

have_{got the} essentialcharacter of the fauna. It contains abso lutely no marine forms and

none

at all'modified

by

^the peculiar environment, _except, perhaps, ^{the brine} fly

(Ephydra), which

^is quite^different from the species inhabiting the GreatSalt

Lake

of Utah.

There

is no Brine

Shrimp (Artemla)

ⁱⁿ anyof the saline springs,

and

it isvery^evidentthatthe origin of the ^salinedeposit

isquite recent

and

even

now

in process of formation

from

the

numerous

saline springs

which

surround the basin both

on

the north

and

south.

At

the surface these springs contain only

from

i to6 per ^{cent, of solid saline} matter, but at a depth ^of

one

^or

two

feetthe brine has a density or 27 per ^cent.,consisting ofboth chloride of

sodium and

sulphate of soda _{(Glauber's salt).}

At

no very remote period ^thisbasin

was

filledwith fresh water, but neither thisnor any other part of theColoradodesertnorth of the

San

_{Jacinto range}

was

ever marine.

OF WASHINGTON. 377 The

SaltonSeaor

Lake

isoneof the greatest natural

wonders

of theworld. Itisashallow_deposit,onlyoneor

two

feet indepth, of solid saline matter

and

is 8 miles

wide and

20 miles long, surrounded

by

^saline springs

which

build

up mounds and

cones ofsaline matter and mattedroots of cane _grass, back of

which

is

the ordinary desert vegetation,gradually disappearing ^{as it} de scends from the level of260feet toabout 265 feet, at

which

_point only oneplantflourishes, andthis plant ^isthe onlypeculiar ^saline plant, outside of thegrasses, to be found in thebasin as far as I

know.

This _plant is Allenrolfeaoccidentalis,

and

I mail

you

herewith a few sticks

which

containlarvaeofaPtinid beetle¹

and

alsoa Clerid

enemy ^and

perhaps

some

other _things. It yields^at last to thesolid induratedcrustof salt

and

soda

which becomes

finallyan

unbroken

_{plain ofpure}salt,the lowest_depression being 280 feet

below

sea level at four miles from the edge ^{of thesalt} plain.

Here

thesoda sinks

below and

formsa.layerabouta foot thickand solid as a rock.

Above

this isa layer ofblack

mud and

then a surface _layerofpure^saltfrom afoot to 18 inches in thick ness.

The

surface ofthesalt isdry and hard, resembling ^ice

and

glistening ⁱⁿ the tropical sun with the million scintillations of a polar^{ice floe;} white, harder and smoother than a sheetof

snow.

I reached Salton late

on

_Saturday

(March

^28).

Sunday was

a fine

day and

^{I devoted the}

morning

^to an examination of thesalt springs

and

the fauna of the basin.

The

^line of debris from the great overflowof the waters of the Colorado River ⁱⁿ ₁₈₉₁

was

plainly^visible

upon

the surface of the salt nearthe shores.

But

every ^stick

and

floatedrailroad tie

was

_solidly fastened

down and

only^afew _spiders lurked under the fragment, evidently living

upon

^insects

blown

out

upon

^{the salt}plain.

Far back

from the

margin

of the lake the earthisstiffened with saline matter,

and

thefeetbreak through^{as in}

walking

^{over cul}

tivated fields

on

_frosty

mornings

ⁱⁿ spring.

Here

there is no vegetation except ^the Allenrolfea

bush growing upon

^small

mounds, and

the grass about the salt springs, but even this last is

encumbered and

encrusted with

snowy

incrustations.

There

islittlechance for insect lifebecause of these thick incrustations,

which

bind

down and

_{solidify every particle} of soil

and wood,

but on the

mounds and

aboutthe rootsof the Allenrolfeabeneath the thin crust isa dry

and

_dustysoil, largelyconsisting of pulver ized salinematter, and here are a few

Hemiptera

^andspiders^;

and

in the larger stems of the Allenrolfea ^I found the larvae

men

tionedbefore.

Where

the springsbreakforth inlarger

volume and

form smallflowingstreamlets there are patches of grass encrusted with mineral matter,

and

even the

mud

_alongthese rivulets is

'ThePtinidbeetlewas successful}'bred atWashington ^and proves ^to be Ctenobium cinereum Horn, originally described from southwestern Texas.

The

Clerid larvahasnotbeenbred. E. A. S.

378 ENTOMOLOGICAL SOCIETY

bordered with ice-like crystals

and

crusts.

Where

these enter the water,

when

turned over they are lined with greenalgae

and upon

thesethere is in vast

numbers

asmall Hydrophilid ⁽Creniphilus n. sp.) with _{pale elytral tip,}

and

in almost _equal

number,

^{in the}

mud

beneath, a palePhilhydrus (Ph.diffusus Lee.) of large^size,

and

less

commonly ^two

species of Ochthebius ₍O. rectus Lee.,

and

_{n. sp.}.} In the surface of theslimypools^is

common

^asalt_fly, evidentlyan

Ephydra,

^{ofbronze color, its}

pupa

^{to be found in} the rust-colored

mud and

_algae under the water.

A

few _insig nificant looking Staphylinidae

(Homalota

and Trogophloeus} ^are tobe found in the_salt-grass

around

the edges^offlowingsprings^; thereisalso Actobius pcederoidesLee. a smallDyschirius(7). in teger}

and some

semiaquatic

Hemiptera

(Salda) ⁱⁿthe

pupa

stage.

There

is finally a small black

Tachys

(

Tachys

corax) running

commonly

^about

^on

^{the salt}

^mud.

Around some

of thesespringyplaces are large

clumps

of a very

tallcane_grass,

which

form

mounds

severalfeetin height.

These

are toodense

and

matted to enter usually, but sometimes,

where

the

mounds

are abrupt

and

not too wet, there ^isa hard crust of salinesoil, under

which

is a moist and even _pasty

mass

of rotten grassⁱⁿ

which two

species of antshave

formed

extensivecolonies.

One

of these is a small red species ⁽

Cremastogaster

sp.), the other a very large pellucid, honey-yellow

form (Camponotus

fragilis},

and

_alwaysin, under, or aboutthese colonies arefound specimens,ⁱⁿconsiderablenumbers,^of

two

species of the

Ca

rabid genus Thalpius⁽Th. dorsails,Lee., hornii Chd.)^{. I}donotsup pose ^{thatthesebeetles are so}

much myrmecophilous

^as they are attracted by ^the

honey dew

of a

Homopteron ^which

^{occurs in}

large colonies

among

^{the ants.}

^The

^{mature insect of this}

Ho

mopteron

^isgrey,withthinbroad wings,

and

the

young

^with

wide

flaringcaudal tufts of

wax.

I have very

few

other insects

from

Salton, but ^I

saw many

frag ments ofa

summer

fauna preserved ^{in the salt crust,}

and among them

there is Cicindela hcemorrhagica,

which

_{certainly belongs}

to the saline fauna.

The

salinefauna of Salton seems tobe_verypoor^{; in fact,there}

istoo

much

salt here,

and

I did not find any ^{of the} Great Salt

Lake

_species. Moreover, ^the investigation of ^this fauna is very difficultbecause everything ^is

cemented

_{solidly by} salt

and

soda sulphate.

Some

discussion ensued

on

the question ^{as to}

whether

the Colorado desert

had

been occupied ^at

any modern

period

by

^an

arm

of the _sea, Messrs.

Vaughan, Schwarz, and

^Gill takingpart.

As

the time for

adjournment

^had not quite been reached at