READING PUBLIC MUSEUM AND ART GALLERY

INTRODuc'rION
As known at present, the tribe Onciderini includes about 250
species, all of which are confined to the New ·World. Of these
only six species occur north of Mexico.
Elongate, ovate or oblong, usualiy robust, cylindrical or otherwise, filllaU to
moderately large in size, ranging from 6 to ncar ly 30 mm. in length. Head at
base about as wide as protborax, not retractile, transverse when viewed from above;
front elongate to slightly transverse, variable in shape, narrowed above or below
(or both) or with sides parallel, flat (rarely convex) when viewed from sides,
parallel w anterior margin of prothorax; eyes deeply emarginatc, sometimes nearly
divided, lower lobe variable in size, usually elongate; antcIlDnJ tubercles prominent,
more or less robust, often n.rmed at apex in male; antennae usually longer in male
than in female, fringed beneath on proximal segments, sometimes densely so; scape
at least attaining apical margin of pronotum, variable in form, without an apical
cic.'l.trix (except in Cicatrodea). Pronotum at least slightly transverse, usually
strongly so; at sides often with a tubere1e placed slightly behind middle. Elytr:l
. usually with humeri prominent, sometimes strongly projecting; elytral apices
rounded together or sep.'\fately (in Ecthoea bident.:l.te); hind w i ngs always present.
Procoxal cavities always closed behind, angulate externtllly; mesocoxal envities
angulated :lIld open externally. Legs variable from short to moderately long;
procoxae large, globose, re:lching nearly to apex and base of prothorax, often armed
in male; femora robust, clavate apically; mesotibi:le sulcate externally, met.'l.tibiae
often strongly dilated apically in male; tarsi nearly as long as tibiae, first three
segments subequnl in length, about as long as broad, first rarely slightly elongate,
claw segment nearly as long as first three together; claws divergent, simple.
Abdomen with first strenite elongate, nearly as long or longer than second and
third together, fifth longer than fourth.
In the Onocephalini which are closely related to the present
tribe, the form of the antennal scape is slender, cylindrical j the
front is slightly convex and is ore strongly inclined tl1un apical
margin of prothorax, and the femora are only feebly clavate, rather
slender. The Hippopsini, including Pachypeza, have the legs very
short, the bead above and the pronotum elongate j the antennal
tubercles are more prominent j and the procoxae are much smaller,
not nearly attaining anterior margin of protbOI'RX.
MORPHOLOGTCAL FEATURES
Most of the critical morphological characters are very variable
within the tribe, DO single cbaracter being dependable in the sepa­
ration of the genera. However, the sLape of the pronotum enables
(v)