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File: <bomby1.ima.htm> [For educational purposes only] Terminology Glossary <Principal Natural
Enemy Groups > <Citations> |
Immature
Stages of Bombyliidae
The eggs of the Bombyliidae, in so
far as they are known, present no adaptive modifications whatever (Clausen
1940). They are oblong in form, are
at times slightly curved, have both ends smoothly rounded, and are 2-4 X
longer than broad. They are
relatively large, measuring 1.0 by 0.25 mm.
in Hyperalonia morio F. and Bombylius fugax Wied.
Apparently all species cover the egg with a coating of mucilaginous
material to which soil particles adhere at the time of deposition. Please CLICK on
picture to view details:
The first‑instar larva of H. oenomaus (Fig. 170A) (Clausen, 1928b) is vermiform, 0.9
mm. in length, and grayish‑white in color. There are 12 body segments which, with the exception of the
last, are of equal width. The head
capsule is heavily sclerotized, its anterior margin is serrated, and it bears
a number of heavy setae. Each
thoracic segment bears a long slender spine, directed laterally, at each
lateroventral margin. The caudal
segment bears a pair of slender spines, which are ca. 1/3rd the body length,
dorsolaterally, each arising from a distinct conical protuberance. Intersegmental welts occur lateroventrally
between the abdominal segments. The
two pairs of spiracles are of simple form and are situated at the anterior
margins of the first thoracic and the last abdominal segments, respectively. The described first‑instar
larvae of other species of the family are similar in all essential respects
to the larva of H. oenomaus. That of B. pumilis
Meig. described by Nielson (1903) is stated to have the lateroventral welts
at the anterior margins or the 2nd to 6th abdominal segments only. The posterior spiracles of this species
are elevated and occur at the posterior margin of the eighth abdominal
segment, rather than on the last segment.
No thoracic spiracles were detected.
The larva of B. fugax Wied. (Seguy & Baudot
1922) is similar to B. pumilis in all characters
mentioned. The mouth hooks of this
species are thought to be paired and articulated. The second‑instar larva has
been described for H. oenomaus and B. pumilis. The body
is rather maggot‑like as contrasted with the vermiform first‑instar
larva. That of H. oenomaus
(Fig. 170B) has 12 distinct body segments with the intersegmental
constrictions very pronounced, is widest in the mid‑abdominal region,
and bears no spines or setae. The
color is mottled white and yellow, the latter due to the large and numerous
fat bodies which are visible through the transparent integument. The two pairs of simple spiracles are
situated at the posterior margin of the first thoracic and eighth abdominal
segments, respectively. The larva of B. pumilis is similar
except that the body segments are of nearly uniform width and the
segmentation is not pronounced. The third‑instar larva has
been described for only a few species.
That of H. oenomaus (Fig. 170C) has 12 body segments and is somewhat
elongated, curved, and widest in the mid-abdominal region. The integument is smooth and glistening,
without setae or other ornamentation.
The posterior spiracles (Fig. 170D), situated somewhat dorsally on
the eighth abdominal segment, are small and crescent‑shaped and have
ca. 12 openings. The anterior
spiracles, at the posterior margin of the first thoracic segment, are of
similar form but less heavily sclerotized.
The larvae of other species are of similar form. That of S. oreas O.S.
is stated to have the anterior spiracles of elliptical form and situated
between the 2nd and 3rd thoracic segments, while the posterior spiracles are
semicircular, with 9-10 openings. In B pumilis, the latter are said to be fan-shaped. In Cyrtomorpha
flaviscutellaris Rob.
(Fuller 1938), the anterior spiracles are larger than the posterior pair and
have 5 slits whereas the latter has only 3, located at one end of the oval
plate. Both pairs of spiracles are
completely concealed by folds of the integument. Each of the first 7 abdominal segments has a pair of spiracles
of minute size. The pupae of Bombyliidae are of
the free type (Fig. 171) and bear a considerable resemblance to those of the
Asilidae, Nemestrinidae, and related forms.
One of the most conspicuous characters is the head crown which
consists usually of three pairs of heavily sclerotized, pointed projections,
or teeth, of which the medium pair may be bifurcate or otherwise
modified. The posterior pair occurs
on the proboscis sheath and are close together. In some species, such as A.
anale Say (Shelford 1913),
the median and anterior pairs are fused at the base to form a fan‑shaped
crown. Each abdominal segment bears a
transverse ring of long slender hairs, and dorsally there is a transverse row
of short, curved hooks. The last
abdominal segment terminates in one or two pairs of short heavy spines. Several species lack the
conspicuous head crown of spines or teeth described above, among these being Systropus conopoides (Kunckel d'Herculais 1905) which bears instead
a pointed plate over the front of the head, markedly similar in form to that
borne by the pupa of its eucleid host, Sibine
bonaerensis Berg., and which
serves the same purpose. References: Please refer to <biology.ref.htm>, [Additional references may
be found at: MELVYL Library ] |
