NEW SCARAB GENERA FROM LOWER AND 
SOUTHERN CALIFORNIA (Coleoptera) 
By Lawrence W. Saylor 
University of California 
I owe to Dr. E. C. Van Dyke and Dr. F. E. Blaisdell the 
opportunity of studying the present new genera, both of which 
exhibit rather interesting structural characteristics. The types of 
both are deposited in the collections of the California Academy 
of Sciences. 
Chaunocolus Saylor, New Genus. 
Facies robust-oval, pilose above. Head with an erect horn, 
clypeus with sides parallel, apex reflected. Thorax with two high 
oblique tumosities each side of middle, the surface between deeply 
concave ; front margin thin but not membranous. Elytra much 
less than twice the length of the thorax, sides without membrane. 
Antennae 9-segmented ; club 3-segmented, the segments close- 
fitting. Eyes from above flat, sunken, inconspicuous. Ligula free 
from mentum. Abdominal segments except last, closely connate, 
the sutures entirely efifaced, the last segment free. Claws long, 
with a minute acute tooth at center. Front femora bidentate. 
apparently without an inner spur. Front coxae conical. Hind 
and middle tibiae with two apical spurs. All tarsi but little longer 
than their respective tibiae; first segment hind tarsus but little 
longer than second. Propygidium and fifth ventral segments not 
connate but separated as in Onccrus, the last spiracle very minute 
and apparently below the suture. 
Genotype : Chaunocolus cornutus, New Species. 
Chaunocolus cornutus Saylor, New Species. 
Robust-oval, rufocastaneous with somewhat piceous tinge, 
strongly shining, pilose above. Head with a stout erect horn at 
center-base of front, the vertex and front each side of the horn 
impunctate and polished, along the eye margin and genae with 
long erect hairs ; clypeal suture not obvious but surface some- 
what transversely obliquely carinate at apparent position of the 
clypeal suture ; clypeus elongate, sides parallel, apex broadly 
evenly rounded ; apex greatly reflexed, sides slightly reflexed ; 
clypeal disc with dense verv- coarse punctures, with short erect 
hair. Antennae 9-segmented, second segment globose, third but 
little longer than second, subcylindrical ; fourth shorter than third ; 
fifth and sixth segments very short and globose ; club oval, sub- 
equal to segments two to six combined. Thorax with sides evenly 
35 
rounded, margin from above very finely crenulate, with very 
dense long yellowish cilia ; front margin thin and seemingly mem- 
braneous but in reality with a fine hair margin ; base finely com- 
pletely margined, with short erect cilia. Thoracic disc with two 
high subcariniform tumosities, these tumosities running from 
each side of middle just in front of the base obliquely forward 
towards the front angles, but suddenly declivious before reach- 
ing the front angles; surface between the two oblique tumos- 
ities deeply widely concave, surface highly polished and very 
sparsely irregularly finely punctured, with a few erect hairs of 
great length ; outer part of tumosities in basal half impunctate, 
in apical half sparsely punctured with moderately long erect hair. 
Scutellum smooth, entirel}^ impunctate. Elytra about one and 
one-half times longer than thorax, surface subrugose, finely ir- 
regularly punctured, with uniform moderately dense suberect 
hair; sutural or other costae not obvious. Abdomen polished, 
with sparse punctures bearing very long erect yellowish hairs, 
the latter denser at sides ; last segment plane, impunctate. apex 
with long cilia. Pygidium polished, very convex, surface mod- 
erately densely fineh" punctured, with very long erect hair ; apex 
subrounded. ciliate. Front tibiae bidentate. Hind femora very 
robust, tibiae short, about twice longer than the width at apex, 
inner face and sides with coarse granulate punctures, with long 
moderately dense hairs; sides with a short oblique carina. Hind 
tarsi one and one-fourth times longer than tibiae, first tarsus a 
little longer than the second, the third to fifth successively a 
little shorter than each preceding segment. Length 4.7 mm. Width 
2.5 mm. 
The unique male Type is from La Paz. Baja California, 
Mexico, collected by G. F. Ferris on June 29, 1919. 
The present genus is related to Oncerus, Pseudacrafus, Podo- 
lasia, and ChnaunantJnts in the mouthparts. spiracles and con- 
nate ventral abdominal segments, but may readily be separated 
from all by the cornute head and the concave thorax. 
Xeropsamobeus Saylor, New Genus. 
Form elongate-oval, somewhat subparallel behind, thorax 
Avidest in apical third, body not narrower in front. Mandibles 
not visible from above. Clypeus grossly tuberculate. Thorax 
evenly convex, with no traces of any transverse ridge or sulcus; 
margin fimbriate with fine hairs. Elytra slightly more than twice 
longer than thorax, verv slightly wider behind, humeral angles 
very prominent and thus probably with well-developed wings. 
Hind tibiae with two transverse ridges; hind tarsi short, only 
slightly triangular, first segment very slightly longer than the next 
two combined, total length of tarsi noticeably shorter than tibiae. 
Front tibiae tridentate. Characters otherwise as in Psammobius. 
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Genotype: Psammobius desertus Van Dyke. 
This distinctive little southern California species, which has 
apparently not been taken since the type, is quite different in 
facies as well as characters from the other U. S. species of 
Psammohms. From those species that are fully winged it dif- 
fers especially in the non-sulcate thorax and more robust elon- 
gate form, as well as the much less triangular hind tarsal seg- 
ments ; from those U. S. species having very short vestigial wings 
(as evidenced by the widely rounded elytral humeral angles) the 
present species differs in the prominent elytral humeral angles 
as well as in the thorax and leg characters cited above. Also, 
most of the species of Psammobius. including two European 
species I have studied, have the margin of the hind tibiae ser- 
rate, while in the present new genus it is smooth. 
AcoMA ROBUSTA Van Dyke. 
This species varies somewhat from the other species of the 
genus so I have included some line drawings in the accompany- 
ing plate to show the general form and salient characters. Ap- 
parently quite locally distributed on the Lower California penin- 
sula, as I have seen no specimens except the type series collected 
by Professor Ferris. 
^^^ 
PLATE 16 
Figure 1. Acoma rohusta Van Dyke. 
Figure 2. Idem. Enlarged view of head. 
Figure 3. Chaunocolus cornutus Saylor, from Type. 
Figure 4. Genitalia of Acoma robicsta V. D. Side view. 
Figure 5. Idem. En face view of genitalia. 
37