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26
BULLETIN OF THE UNIVERSITY OF NEBRASKA STATE MUSEUM
Temporal Distribution. Rangewide:
March to October (Peck and Kaulbars 1987).
Nebraska: May (2), June (37), July (34),
August (10), October (3).
Remarks. Heterosilpha ramosa is easily
recognized because it is the only silphid in
North America that is entirely black, with
distinctly tricostate elytra, and with the
costae branching and weakly shining against
a dull black background.
The larval stage was described by
Gissler (1880), Dorsey (1940), Brewer and Bacon
(1975), and Anderson and Peck (1985).
Brewer and Bacon (1975) studied the
natural history of this species in Colorado,
and their observations are probably representative
for Nebraska as well. Adults
overwinter and become active the following
spring when temperatures become warm.
Eggs are laid in the soil around a carcass,
and this stage typically lasts 5 days. The
first instar takes 4-5 days, the second instar
5-6 days, the third instar 8-10 days, and the
pupal stage 8-9 days. The period from egg
to adult lasted about 30 days. There are two
generations a year with adults of the first
brood (in Nebraska) appearing in June and
those of the second in late July and August.
Genus NecRODeS
Necrodes Leach 1815: 88.
Asbolus Bergroth 1884: 229.
Protonecrodes Portevin 1922: 508.
The genus Necrodes contains five
species (Hatch 1928) distributed in North
America, Europe, and Asia. There is only
one species in North America, and it is found
throughout Nebraska. There is no modern
taxonomic treatment of the genus, and the
most recent world catalog is Hatch (1928).
Madge (1980) reported that Bergroth
(1884) believed that the name Asbolus was
validly published by Voet (1778) and proposed
that it replace Necrodes Leach 1815.
However, Voet’s work was not consistently
binomial and thus is not available for zoo-
logical nomenclature according to the Code.
Asbolus, therefore, dates from Bergroth
(1884) whose action can be regarded as the
proposal of an unnecessary nomen novum.
While life history information is probably
generally known for all of the species,
only the North American N. surinamensis
has been studied in detail (Ratcliffe 1972).
The genus Necrodes is easily recognized
because of its large eyes, broadly orbicular
pronotum, strongly tricostate elytra, and
males with enlarged posterior femora. The
larvae are distinctive because the basal segment
of the urogomphus is more than twice
as long as the tenth abdominal segment.
Necrodes surinamensis (Fabr.)
(Figs. 18-19, 23-24, 34, 49-56)
Silpha surinamensis Fabricius 1775: 72.
Protonecrodes surinamensis bizonatus Portevin
1926: 165.
Diagnosis. Length 12.0-24.0 mm. Head:
Color black, widest across large eyes. Antenna
11-segmented, gradually clavate.
Labrum broadly, shallowly emarginate.
Thorax: Pronotum shining black, orbicular,
widest near middle. Surface densely punctate,
punctures small. Elytra: Color black,
usually with subapical, transverse row of
1-5, small, reddish orange spots variously
combined; occasionally with subbasal, transverse
row of 1-3 spots; rarely immaculate.
Surface strongly tricostate, with short costa
at base between costae 2-3. Surface densely
punctate, punctures moderately large. Legs:
Foretarsi of males with segments 1-4 usually
expanded, as wide as long; in females, segments
a little longer than wide. Males with
hind femora usually enlarged and with acute
tooth on posterior edge; femora not enlarged
or toothed in females (Figs. 18-19). Posterior
tibia usually curved in males, straight in
females.
Distribution. Necrodes surinamensis is
broadly distributed in the eastern United
States east of the Rocky Mountains and in