Female: 2.15 mm; a = 52; b = 10; c = 19.2; V = 52
Male: 1.7 mm; a = 52; b = 9; c = 14.7
Characters of the genus.
Lip region set off by deep constriction, bearing about nine annules.
A face view shows the head to be four-lobed, with deep lateral grooves
in which the amphid apertures are located. These grooves are in alignment
with the lateral body lines, which extend to the lip region. Labial
disc a prominent feature. Spear 157 u long, with strong, rounded
knobs. Esophageal lumen convoluted in procorpus when spear is retracted.
Median bulb spherical, more than half as wide as neck. Nerve ring
almost adjacent to median bulb. Hemizonid adjacent to excretory pore.
Basal portion of esophagus extended in a broad lobe. Junction of
esophagus and intestine an obscure muscular valve. Intestine extending
into tail cavity, with rectum attached ventrally. Ovaries outstretched,
with spermatheca. Phasmids of both sexes slightly anterior to middle
of tail. Male tail enveloped by bursa, which rises anterior to spicula.
Belonolaimus gracilis is distinguished from B. longicaudatus
by the shorter tail, longer spear, and greater relative width.
Hosts and distribution: Slash pine, Pinus caribaea Morelet,
Ocala, Florida, and longleaf pine seedlings in forest nurseries in other
parts of the state. According to Rau, Belonolaimus gracilis
has a very limited distribution.
(Description- Thorne, 1961)