Immature Stages of Ceraphronidae
Immature stages of Ceraphronidae (= Calliceratidae) were discussed in detail by Clausen (1940), as follows:
Clausen (1940) noted the family Ceraphronidae as Calliceratidae. The egg and larval instars of several species of Lygocerus and Conostigmus in the Cephronidae have been observed and described. In Lygocerus, four larval instars are recorded for L. cameroni, L. niger, and Lygocerus sp. from Japan, with some evidence presented that an additional instar may intervene between those described as the first and second. Kamal, however, found only three instars in C. zaglouli and C. timberlakei.
The egg of L. cameroni is elliptical in form, 0.25 mm. in length, and white in color, with a minute protuberance at one end, and the chorion bears minute longitudinal striations. That of Lygocerus sp. (Fig. 115A) is similar, though the nipple‑like protuberance at the posterior end is considerably narrowed. In L. niger, there is a similar protuberance at the anterior pole, also.
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The first‑instar larvae of L. cameroni and Lygocerus sp. (Fig. 115B) are similar in form and have relatively large, rounded heads, followed by 12 body segments, with the greatest width occurring in the anterior abdominal region. The mandibles are minute and slender and are adapted for penetrating only a delicate host skin. The integument bears no sensory setae or cuticular spines. There arc two pairs of spiracles, one situated on the intersegmental membrane separating the fir#t two thoracic segments, or at the anterior margin of the second, and another on the first abdominal segment. The larva of C. timberlakei is distinguished by the size and form of the last abdominal segment, which equals the four preceding segments in length and is deflected ventrad. No mention is made of the respiratory system.
The second‑instar larva of L. cameroni is distinguished from the first by the possession of an additional body segment and four pairs of spiracles, these being situated at the anterior margin of the second thoracic and on the third thoracic and the first two abdominal segments.
The third‑instar larva of L. cameroni is more robust than the second, being somewhat globose, with the head markedly ventral in position. There are seven pairs of spiracles, the first being situated at the posterior margin of the first thoracic segment and the following ones on the third thoracic and first five abdominal segments. Spiracular branches may also be found in the second thoracic and the sixth abdominal segments. The third‑instar larva of Lygocerus sp. (Fig. 115C) differs from the above in the more elongated form of the body and the presence of transverse rows of conical protuberances dorsally and laterally upon all body segments except the last. The caudal segment is somewhat irregularly bilobed transversely.
The mature larvae of L. cameroni, L. niger, and Lygocerus sp. (Fig. 115D) are similar in all principal characters. The body is robust, broadest in the thoracic region, and curved or straight according to the cell that it occupies. The head is relatively small, with simple mandibles. In all these species, the last abdominal segment is transversely bilobed, the dorsal lobe being distinctly conical in form. The thoracic and all abdominal segments except the last bear conical papillae or tubercles on the dorsum and sides, which are arranged in transverse rows in L. niger and Lygocerus sp, and are scattered in L. cameroni. In the latter species, they occur also upon the conical process of the last abdominal segment. There are seven pairs of spiracles, situated at the posterior margin of the first thoracic segment and on the third thoracic and first five abdominal segments. In Lygocerus sp., these are markedly dorsal in position, and the pair on the third thoracic segment is much the largest.
The mature larva of Conostigmus, which is stated by Kamal to be the third instar, lacks the principal characters that readily distinguish Lygocerus. The conical integumentary papillae and the conical process on the last abdominal segment are lacking. The head is exceptionally large and hemispherical, and the last abdominal segment is longer than those preceding it and smoothly rounded. In C. zaglouli, each abdominal segment, except the last, bears a sclerotized ring, which is much heavier ventrally than on the dorsum. There are eight pairs of large spiracles, whereas C. timberlakei has only six, situated on the first thoracic and the first five abdominal segments.