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KEY TO THE SPECIES OF THIRD
INSTAR LARVAE
OF NICROPHORUS IN NEBRASKA
(modified from Anderson 1982)
1. Abdominal segment 10 with venter
unsclerotized at base. Abdominal segment
9 with sclerotization of sternite fragmented
(Fig. 102) or else truncated at lateral margins
(Figs. 100, 103) . . . . . . . . . . . . . . . . . . . . . 2
1’. Abdominal segment 10 with venter
sclerotized at its base. Abdominal segment
9 with sclerotization of the sternite entire,
straight along posterior margin, arcuate and
emarginate at middle along anterior margin
(Fig. 101) . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Abdominal segment 9 with sclerotization
of sternite fragmented (Fig. 102) . . . . . .
. . . . . . . . . . . . . . . . . . . . marginatus Fabr.
2’. Abdominal segment 9 with sclerotization
of sternite entire and truncated along
lateral margins (Figs. 100, 103) . . . . . . . 3
3. Abdominal segment 3 with lateral and
mid-dorsal spines equal in length (Fig. 103).
Ligula without lateral lobes . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . obscurus Kirby
3’. Abdominal segment 3 with mid-dorsal
spines about 3 times length of lateral spines
(Fig. 100). Ligula with small lateral lobes . .
. . . . . . . . . . . . . . . . . guttula Motschulsky
4. Abdominal segment 10 with y-shaped
sclerite on venter in apical half, sclerite extending
to bases of innermost pair of apical
setae . . . . . . . . investigator Zetterstedt
4’. Abdominal segment 10 not sclerotized
on venter in apical half . . . . . . . . . . . . . . . 5
5. Abdominal segment 1 with lateral and
mid-dorsal spines equal in length. Dorsal
spines at middle of segments 2-8 at least
twice as long as lateral spines. Lateral spines
of segments 1-8 short, not exceeding diameter
of spiracle . . . . . tomentosus Weber
5’. Abdominal segments 1-3 with lateral
spines slightly longer than or equal to middorsal
spines. Mid-dorsal spines of segments
4-8 at least twice as long as lateral
spines. Lateral spines of segments 1-8 long,
approximately twice diameter of spiracle on
segments 6-8 . . . . . . . . . . . . . . . . . . . . . . . .6
THE CARRION BEETLES OF NEBRASKA 59
6. Abdominal segment 9 with large lateral
spines. Distance between the base of
urogomphus and base of lateral spine subequal
to length of lateral spine . . . . . . . . .
. . . . . . . . . . . . hybridus Hatch & Angell
6’. Abdominal segment 9 with minute
lateral spines, appearing as small cones.
Distance between base of urogomphus and
base of lateral spine at least 4 times length
of lateral spine . . . . . . . . orbicollis Say
Fi g s. 100-103. Ventral view of ninth abdominal segment
of larva of 100, Nicrophorus guttula; 101, N.
investigator; 102, N. marginatus; 103, N. obscurus
(after Anderson and Peck 1985).