T ¼ tail length.
D% ¼ EP/ES Â 100.
E% ¼ EP/T Â 100.
SW ¼ spicule length divided by anal body width.
μm ¼ micrometers.
Key to Species
of the Genus Steinernema
(Fig. 12)
1. Infective juvenile (IJ) with a double-horn-like structure
on labial region
S. bicornutum
IJ without a double-horn-like structure on labial region 2
2. Body length of infective juvenile (IJ) >800 μm
3
Body length of IJ <800 μm
1 0
3. Average length of IJ >1000 μm (1034–1171); male tail
without mucron
4
Average length of IJ less than 1000 μm (849–951); male
tail with or without mucron
8
4. Tail of IJ <85 μm (67–78); E% >106 (119–160);
female without epiptygma
5
Tail of IJ averaging >90 μm (95–95); E% <105
(85–101); female with or without double-flapped
epiptygma
7
5. SW ratio about 1.4, spicule about 58 μm (50–67), E%
about 160
S. cubana
SW ratio about 2.0, spicule length >72 μm (77–84); E%
<140
6
6. In IJ, distance from anterior end to excretory pore
76–86 μm; in male, D% about 93 (88–102), spicule
84 μm long with tip swollen
S. anomali
In IJ, distance from anterior end to excretory pore
87–110 μm; in male, D% about 70 (60–78), spicule
77 μm long, spicule tip with large aperture resembling a
notch
S. glaseri
7. E% averaging 101 (88–108); in male D% about 77
S. puertoricensis
E% averaging 85 (range not known); in male D% about
62
S. longicaudum
8. In IJ, distance from anterior end to excretory pore
extremely short, 18 μm (14–22), E% ¼ 23; in male, D%
averaging 19 (13–25)
S. neocurtillis
(continued)
Morphological Characterization
75