|
File: <eupel1.ima.htm> [For educational purposes only] Terminology Glossary <Principal Natural
Enemy Groups > <Citations> |
Immature Stages
of Eupelmidae
Immature stages of Trigonalidae were discussed in detail by
Clausen (1940), as follows: There is little variation in form among the eggs of the
representatives of the Eupelmidae.
The main body of the egg is ellipsoidal and bears a stalk of varying
length at the anterior end. In A. albitarsis (Fig. 83A), this stalk is only one‑third
the length of the egg body and is robust and turgid after deposition. There is no pedicel or flagellum at the
posterior end, but only a minute tubercle.
In other species of this genus and in other genera, the stalk is
longer, at times equaling or slightly exceeding the egg body, and more
slender and there is a tapering "flagellum" at the opposite end of
the egg (Fig. 85A). After deposition
of the egg, the stalk is usually convoluted or sharply bent. The eggs of this family are relatively
large, ranging from 0.3 tb 0.7 mm. for the length of the main body. The first‑instar larvae of the genus Anastatus are distinguished by a rather elongated form and
the development of the last abdominal segment into a bifurcated process. The extreme modification in form within
the genus is revealed by A. albitarsis (Fig. 83B), found in
lepidopterous eggs (Clausen, 1927).
The paired processes of the tail are curved and heavily sclerotized
and lie at right angles to the plane of the body. The second and third thoracic and the first seven abdominal
segments each bear a transverse row of long spines ventrally at the anterior
margin. Those of the first row equal
about three body segments in length, and they diminish in size on the
successive segments. Other species of
the genus show the above characters in a lesser degree (Fig. 84A), though in
some the ventral spines are not arranged in a distinct row and do not
appreciably exceed the dorsal spines in length. Please CLICK on pictures to
view details:
The larvae of Eupelmus
and other genera in which the first instar is known lack the bifurcation of
the caudal segment and have a relatively small number of spines. That of E. allynii
(Fig. 85C) has two pairs of long spines dorsally on each body segment except
the last and one pair of smaller spines ventrally on each thoracic
segment. The integument is densely
clothed with minute setae. In Arachnophaga, one pair of
spines is dorsal and the second lateral, just beneath the line of the
spiracles. The integument of the
dorsum and side bears numerous peg‑like projections. The larva of E. cicadae
is slender, with a large and heavily sclerotized head, and the segmental
spines are very much reduced in size.
That of Eupelmella vesicularis bears two pairs of
long heavy spines on each body segment, with an additional shorter pair on
each of the thoracic segments. The tracheal system of this instar normally bears four pairs of
spiracles, which are situated on the second thoracic and the first three
abdominal segments. In Eupelmus allynii, however, an additional pair is found on the
metathorax The studies made upon Anastatus,
Eupelmus, and Eupelmella indicate that there
are normally five larval instars, with the intermediate and final instars
quite similar in form. In Anastatus, there
appear to be two forms of mature larvae, one being that of A. albitarsis (Fig. 83D) and A. semiflavidus,
in which the body is robust, almost cylindrical, curved to conform to the egg
in which it develops, and bearing only a few minute setae, and the other,
represented by A. disparis and Anastatus sp. (Fig. 84B), which
is almost spherical in form. The
latter bears short spines on the thoracic segments and a larger number on the
sixth to ninth abdominal segments. In Eupelmus, Eupelmella and Lecanobius, the mature larva is
rather elongated as compared with that of Anastatus. Eupelmus
allynii (Fig. 85D) bears about seven pairs of long
spines on the first thoracic segment, five pairs on the second and third, two
pairs on the first five abdominal segments, and three pairs on the last five
abdominal segments. Those on the
abdomen are considerably shorter than the thoracic spines. Among the different species, the principal
variation is in the size of these spines.
The mandibles are simple. The
number and position of the spiracles are constant in all the known genera,
there being nine pairs, situated on the second and third thoracic and the
first seven abdominal segments. There is little variation in the form of the pupae within the
family. Some have the body greatly
curved, to conform to the outline of the egg in which they have developed,
whereas others not so closely confined are more slender and the parts of the
body are in the same plane. A. albitarsus is the only species known to possess the three fleshy
processes on the head superimposed over the developing ocelli (Fig. 83E). References:
Please refer to <biology.ref.htm>,
[Additional
references may be found at: MELVYL Library ] |
