BEETLE GENUS ONTHOPHAGUS — HOWDEN, CARTWRIGHT 91 In hopfneri (usually labeled arizonensis) , the yellow is usually a

brighter yellow

compared

to the reddish yellow or brownish yellow of schaeferi; theyellow is always

much more

extensive, the base

and

apices of theelytra usually solid yellowwith

numerous

small, round, yellow spots in between; the 8th elytral interval is solid yellow pos- teriorly.

Dr. A. Villiers kindly checked a specimen of schaefferi with

Har-

old's specimens of allied species in the

Museum

National d'Histoire Naturelle

and

reported

no

similar specimens were represented.

The

writers' observations indicate that 0. schaefferi is less abun- dant than /. texanus, though the

two

are often taken together in shaded habitats in the lower

Rio Grande

Valley.

They

are attract- ed to excrement of

many

different animals.

The

species is

named

after Charles Schaeffer

whose

1914 revision of Onthophagus hasserved

American

entomologistsforoverfiftyyears

Onthophaguslandolti texanusSchaeflfer Plate 6, Figures46-48

Onthophagus texanus Schaeffer, 1914, p. 299.

—

^{Leng, 1920,} p. 249.

—

Boucomont andGillet, 1927, p.208.—Robinson, 1948, p. 176.

Onthophaguslandoltivar. texanus (Schaeffer), Boucomont, 1932, p.314, 326.

Male

majors.

— ^Length

^{4.6 to 5.3}

^mm.,

^{width 2.8 to 3.1}

mm.

Head and pronotum

shining, piceous to black, rarely with faint greenish cast, usuallywith anteriorangles

and

anteriorlateralmargins of

pronotum

narrowlybrown. Elytra variable, frequentlyblackwith humeralspots

and

apicalportion yellowishbrown, occasionallylargely brown, with only sutural interval

and

parts of intervals behind the humeri black; quite often with alternate black

and brown

intervals, giving a stripedappearance, the sutural

and

alternate followinginter- vals black, always with a marginal black spot

beyond

4th

and

5th intervals.

Pygidium

bicolored, centrallypiceous or black,marginally brown; ventral surfaces piceous to blackwithlateral marginsof abdo-

men and

legs

brown

to dark bro^vn.

Head

with clypeus extended

and

abruptly reflexed anteriorly, scarcely reflexed

and

obtusely arcuate laterally; a bidentate appearance resulting

from

broadly emarginate

and

laterallyabruptlyangulatereflexed portion. Clypeal disc flat

and

smooth, very finely punctate medially, with a

few

scat- tered, moderate, setigerouspunctures laterally; clypeal carina absent;

frons fimelypimctate,smooth, shinmg,

and

almostflat; genae scarcely flared, sm-face

smooth

to finely alutaceous with scattered, moderate, setigerouspunctures; vertexslightlyelevatedbut withcarinaobsolete, sm'face

smooth

to alutaceous

and

nearly impunctate.

Pronotum

finely margined anteriorly, lateraUy

and

basally very finely at middle; anterior angles sharply rounded;

pronotum

wider

92 PROCEEDINGS OF THE NATIONAL MUSEUM

^{vol. lu}

near the middle, moderately convex with a small median,

somewhat

flattened, conical projection extending over the anterior margin; the projectionbasally

bemg

scarcely as

mde

as the^reflexed portion of the clypeus; pronotiim coarsely pmictate except for tip of the projection

and

for a

narrow band

justbehind the anteriormargin; the punctures separated

by

¹ to 3 diameters

and

bearing fine, brownish, inconspicu- ous setae; surface between the punctures

smooth and

shining to mi- nutely alutaceous except near the

median

portion of the posterior

margin where

it

may

befinely alutaceous. Elytrawith faintly punc-

tate, shallow, shining striae; intervals except for sutural interval irregularly biseriately tuberculate, the tubecles bearing small setae at their posteriormargins;surface between the tubercles veryfinely alu- taceous.

Pygidium

coarsely, setigerously punctate, surface between thepunctureslargely

smooth and

shining, particularlyon

and

nearthe convex apex. Ventral surfaces of thorax coarsely, setigerously punc-

tate, laterally with surfaces finely alutaceous;

median

line of meta-

sternum

oftenslightlyindented

and

impunctate.

Abdominal

segments each with a basal

row

of setigerous punctures, often obsolete medially, last

segment

emarginate medially toreceive the pygidium. Forelegs elongated, theapexofthefemora extending

beyond

thelateralmargins of the pronotum. Foretibia similarly lengthened, quadi'identate;

outer

margin

dentateorserratebetween

and

abovethe teeth, bentin- wardlyin apicalhaK, thetipextended overtheapicalspine

and

usueJly bearing a pencil of hairs.

Middle and

hind legsnotgreatlyelongated, the femora with a

few

scattered setigerous punctm'es.

Male

minors.

— Length

3.1 to 4.1 nmi., width 1.8to 2.8

mm.

Dif- feringfromthe

male

majorsinthe following respects: Fullyasvariable in color, butusually lacking greenish caston the

head and

pronotum.

Head

with clypeus emarginate anteriorly but not greatly reflexed;

disc ofclypeus,frons,

and gena

asdescribedfor

male

majors. Clypeal carina absent, the areaofthe carinasometimesslightlytmnid; vertex with a small tomoderate,nearly straightcarina extending about two- thirds of the distance

between

the eyes.

Pronotum

less convex than in

male

majors withpronotal projection only vaguelyindicated,rarely completelyabsent, punctures extendingto anteriormargin;

pronotum

in other respects similar to

male

majors. Elytra exhibiting all the variationsin color

mentioned

for

male

majors.

Pygidium and

ventral surfaces generally similar to those of

male

majors, but with setae

and

punctures often

more

pronounced. Forelegs not greatly extended, femora not extending to lateral margins ofpronotum, foretibiashort, scarcely bent, lacking apical conical projection over spine

and

pencil ofhair, tibial teeth often slightly larger than in

male

majors; similai in otherrespects.

BEETLE GENUS ONTHOPHAGUS — HOWDEN, CARTWRIGHT 93 Females. — ^Length

^{3.8 to 5.2}

^mm.,

^{width2.5 to 3.0}

mm.

Differing from the

male

majors in the following respects: Color exhibiting all

the variations noted including the shining greenish cast.

Head

with clypcus

more

sharply emarginate, moderately reflexed anteriorly

and

laterally; clypeal disc flat, coarsely, almost rugosely punctate; a low clypealcarinapresent,highestmedially;fronsand genae withscattered, moderate,setigerouspunctures^;vertexwitha

moderate

carinaextend- ing approximately two-thirds the distance between the eyes, nearly straight

and

level, occasionally indented medially or bent posteriorly at the ends; vertex behind the carina withscatteredcoarsepunctures.

Pronotimi asdescribedfor

male

minors withthe pronotal projection either absent or barely indicated, setae often

more

pronounced than

in

male

majors. Elytra similar except forslightly

more

pronounced tubercles

and

setae.

Pygidium more

evenlyconvex, otherwisesimilar

;

ventral surfaces with

more

pronounced punctures

and

setae; last abdominal

segment

not

narrowed

medially to receive the pygidium.

Forelegs not extended, the femora not reaching the lateral pronotal margins; tibiae stocky, the four teeth larger than in males, margin between

and above

teeth usually denticulate or senate; apical pro- jection

and

pencil of hairs lacldng; in other respects not noticeably differentfrom males.

Type.

— ^Of

^{fexanus Schaeffer: Lectotype, present} designation, _9,

USNM

42592, Brooklyn

Museum

Collection, 1929. Cotypes, 2 9 9,

were collected

on

the Esperanza ranch, Brownsville, Tex.,

May

29, 1903.

Of

landolti Harold:

Museum

National d'Histoire Naturelle, Paris, France.

Type

^locality.

— ^Of

^{texanus Schaeffer:} Brownsville, Tex.

Of

landolti Harold: Ocafia, Colombia,

and La

Guayra, Venezuela.

Specimens examined. —

^424.

Distribution.

—

(See^fig. 1, p. 17.)

Oklahoma: Marietta. Texas: Bentsen-RioGrandeStatePk. (nearMission), Brownsville, Lake Corpus Christi State Pk., west Cameron Co., Garner State Pk., southwestHidalgo Co.

Biology.

— Some

specimenswere brought

back

alive to the Univer- sity ofTennessee, placedinlarge earth-filledflowerpots,

and

furnished with fresh

cow

dung.

Under

these conditions the beetlesreproduced readily.

The

female beetles

made

winding 3-to-7-inch burrows with a cell of

dung

at the

bottom

of each burrow.

Twenty

cells were measured,the longestbeing 16

mm.,

the shortest 10

mm.

;inwidth they ranged

from

7 to 11

mm. The

average cell

was

12 to 14

mm.

^long

and

8 to 9

mm.

wide.

94 PROCEEDINGS OF THE NATIONAL MUSEUM

^{v'".. ii4}

The

female

made

the cell

by

packing the

dung

into the

end

of the

burrow and making

a small cavity in the upper

end

of the dung.

A

single elongate oval egg 0.8 to 0.9

mm.

long

and

0.3 to 0.4

mm,

wide

was

fastened

by

one

end

to the side of thecavity.

Each

female produced

from

3 to 30eggs.

Two

females placedin a flowerpot with a single

male

produced 55 cells.

Development was

rapid, the eggs hatchingin 2 to 4 days, the first

two

instarslastmg

from

7 to 10 days

and

the third Lnstar 12 to 14 days. (A discussion of the length of development,picturesofthe larva

and

adult,

and

theeffectsof

gamma

radiation

on development have

been

pubhshed

elsewhere. See

Howden,

1957).

Larvae

that were observed hatching

August

2

became pupae

^on

August

31. Before pupation, the larva forms a hard spherical pupal cell of its

own

feces inside the

dung

wad.

The

pupal periodlasts only 5 to 7 days but the teneral adult

may

remain in the pupalcellforseveralweeks.

Once

the adult emerges, mating, though not observed, apparently is not long delayed, for females start cell formation shortly after their appearance. It is interesting to note thatisolated virgin females do little burrowingin comparison with

mated

females. Active beetles lived for 2 to 3

weeks

under laboratory conditions.

At

least six generations were reared, starting with the

two

femalesfertilized

by

asingle male.

At

almost

any

point in the above cycle, adverse conditions

may

change the length of time required for development. Either too moist or too dry conditions in the flower pots caused considerable mortality. Moistm-e favored the appearance of fungi in the cells.

However,

mites were the

most

difficult

problem

tocontend with inthe flower pots; frequent changes were necessary, because if the adults wereleftinpots

where

themite population

was

large, themites

would

actuaUy kill the beetles. Occasional specimens in the field

have

been noted infested with mites, but

how

serious a pest they are to the coprophagous beetlesremains aninteresting problem.

Kemarks. — ^Boucomont

(1932) placed 0. texanus as a variety of 0. landolti,

and

unquestionably it is very close.

We

prefer at present to give texanus subspecies status. It differs

from

typical landolti in that it is less shining

and more

noticeably alutaceous.

The pronotum

is

usuaUy

black or brown, onlyrarely with a greenish cast, whereas in landolti it is frequently bright green or coppery.

The pygidium

is always bicolored, often being yellow over

more

than half its surface,

but

in landolti the

pygidium

is black or only the edges are narrowly yellow.

The

apical black spot of the elytral declivity is

more romided

higher up,

and

is opposite the 4th

and

5th intervals; in landolti thespotiselongate,nearer the edge,

and

opposite intervals 3, 4,

and

5; the males of texanus never

have

the anterior arcuate pronotal carina which is sometimes evident in landolti.

BEETLE GENUS ONTHOPHAGUS ^HOWDEN, CARTWRIGHT 95