File: <betho1.ima.htm> [For educational purposes only] Terminology Glossary <Principal Natural
Enemy Groups > <Citations> |
Immature Stages of Bethylidae
Immature stages of Bethylidae were discussed in
detail by Clausen (1940), as follows: Though extensive observations have
been made upon the habits of a number of species of Bethylidae, yet in few
instances have the early stages been adequately described. The eggs of the different species
are quite similar, being elliptical to elongate-ovoid, 0.3-1.5 mm. in length
and 2-4 X as long as wide. Usually
they are slightly curved, with the anterior end broader. The chorion is smooth and glistening
except in Prorops nasula, which has a granulated
or reticulate surface. The first‑instar larva of Perisierola gallicola (Fig. 147) is robust,
with the segmentation indistinct. The
head is large and nearly hemispherical.
There are eight pairs of spiracles, situated on the first and third
thoracic and the first six abdominal segments. Please CLICK on
picture to view details: The number of larval instars is
known for only a few species.
Williams (1919a) recorded four for Epyris
extraneus and five are
described for Cephalonomia gallicola and for Laelius anthrenivorus (Vance & Parker 1932). The larval instars show little
variation in their general characters.
The early instars are usually indistinctly segmented and often
pyriform, with only the main body divisions indicated. The third‑instar larva of C. gallicola bears a pair of long setae on the median ventral
line of the first thoracic segment.
The mature larvae are usually unornamented, with the integument thin
and transparent. In P. gallicola, however, there is a transverse band of
backwardly directed papillae on each thoracic segment, and a few fine hairs
on the abdomen. The mandibles are also an
extremely variable character, though they are large and protruding in all
species. In E. extraneus,
they are simple in the first instar, bidentate the second, and tridentate in
the third sod fourth instars, and those of the successive instars of L. anthrenivorus have two, three, five and seven teeth. In P.
gallicola, they are simple
in the mature larva, and presumably in the early instars also. The number of spiracles is
decidedly variable among the different species. P. gallicola (Silvestri 1923b) has eight pairs in the
first instar, situated on the second thoracic and first seven abdominal
segments, and on the mature larva additional pairs appear on the third
thoracic and eighth abdominal segments.
B. cephalotes (Richards 1932) also
has eight pairs in the first instar.
In contrast to this, L.
anthrenivorus has a single
pair on the second thoracic segment in all instars, and C.gallicola
and C. tarsalis have five pairs in all instars. The cocoons are oblong or somewhat
cylindrical in form and tough and firm.
In E. extraneus, the anterior end is
less firm and is closed off by a neat disk, which is cut away at the time of
adult emergence. The cocoons of P. emigrata and several other species are white and delicate
and may be loosely woven. References: Please refer to <biology.ref.htm>,
[Additional references may be found at: MELVYL Library ] |