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File: <eucha1.ima.htm> [For educational purposes only] Terminology Glossary <Principal
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Immature Stages
of Eucharitidae
Immature stages of Eucharitidae (= Eucharidae) were
discussed in detail by Clausen (1940), as follows: The eggs of the
Eucharitidae are all of the stalked type and, because of the enormous numbers
produced by each female, exceedingly minute.
The egg body is ellipsoidal in form and greatly arched dorsally and ranges
from 0.1 to 0.2 mm. in length in the different species. The slender anterior stalk is one‑fourth
the length of the egg body in Psilogaster
montanus as compared to
twice its length in Psilogaster
sp. and Stilbula cynipiformis. At deposition, the eggs are translucent,
but as incubation progresses they assume a deep amber color, with the heads
of the larvae appearing almost black. The first‑instar
larvae are all of the planidium type, distinguished by a large, heavily sclerotized
head and heavy, segmental bands that terminate lateroventrally in pleural
plates. Transparent membranes, which
are not visible until feeding takes place, separate these bands and in active
individuals the successive segments telescope into those preceding. Because of this, it is difficult to
determine the exact number of body segments; but from on examination of cast
skins, in which the bands are somewhat separated, the normal number appears
to be 12, with the 13th segment represented by the unsclerotized caudal
sucker. Please CLICK on
picture to view details:
The
greatest morphological differences between species are found in the form and
in the spine equipment of the pleural plates. In Chalcura deprivata (Fig. 99), those of
the first two segments are rounded, whereas on the following six segments
they terminate in long, posteriorly directed spines which are free, except
at the base. The posterior margins
of the plates are notched, and those of the fourth and fifth abdominal
segments bear a second pair of spines.
The paired spines of the latter segment are twice the length of those
preceding. The sixth to ninth
abdominal segments have the segmental bands but no pleural plates, and the
caudal cerci are borne dorsolaterally on the eighth segment. Sensory spines and setae are as shown in
the figure. In Schizaspidia manipurensis
(Fig. 99), the sensory spines of the pleural plates are much longer than in Chalcura, and Kapala foveatella, described by Ishii, has the distal portion of
the plates of the fifth abdominal segment greatly produced and projecting beyond the end of the
body. Several species of other genera
show a less pronounced modification of the plates of this segment. The spiracles, if present, are
exceedingly small and difficult to distinguish. In S. manipurensis, the single pair
is situated at the anterior margin of the prothorax. The second‑instar larva was
known only in S. tenuicornis, K. terminalis and Stilbula
cynipiformis by 1940
(Clausen 1940). That of Schizaspidia tenuicornis (Fig. lOOB) is
shining white, with only nine distinguishable body segments, and the head is small,
not heavily sclerotized, and situated ventrally. There are no sensory setae or integumentary spines. In K.
terminalis, the body is bag‑like,
with only faint indications of segmentation, and a single pair of spiracles
is situated at the anterior margin of the mesothorax. Parker's (1932) examination of the 2nd
exuviae of Stibula cynipiformis revealed a lack of
segmentation, several transverse rows of minute setae, and two pairs of
spiracles. The mature larvae, which are the
third instar, are robust in all species, and they differ principally in the
distinctness of segmentation, the presence or absence of dorsolateral
tubercles, and the integumentary ornamentation. The larva of Schizaspidia
tenuicornis shows no
segmentation except for constrictions between the three principal parts of the body. This is true of several other species, but
in Eucharis sp. the
segmentation is distinct. Large
dorsolateral tubercles on the first 10 body segments have been noted only in Orasema. All species bear an anal lobe, usually
hemispherical is form, which may represent the last segment. Although sensory setae and
integumentary spines are lacking, yet the body is completely or partly
covered with minute papillae or tubercles. There are usually nine pairs of
spiracles, situated on the second and third thoracic and the first seven
abdominal segments, though in several species there are said to be only
eight. The two pairs on the thorax
are much the largest. It has been pointed out by Parker
that the larva of Slilbula cynipiformis is devoid of
tegumentary muscles, and this appears to be a normal condition in the
family. In no species observed is the
mature larva capable of ordered movement, and in many there is no visible
physical reaction when they are disturbed. The pupae of the Eucharidae
present few distinguishing characters except in those species which have the
scutellum produced into a bifurcate process, in which cases the pupal form is
correspondingly modified (Fig. lOOD).
The abdomen of the female is very large and bears intersegmental
ridges over the dorsum and sides.
Some species of Orasema,
Schizaspidia, Kapala, and Chalcura bear welts on the
lateral portions of these ridges.
These welts, or pustules, are most pronounced in 0. coloradensis;
the ridges of O. viridis are unmodified. The welts are globular in form and much
constricted at the base and occur only on the posterior thoracic and petiolar regions, in 0. costaricensis. References: Please refer to <biology.ref.htm>,
[Additional references may be found at: MELVYL Library ] |
