Immature Stages of Sarcophagidae
The eggs of the Sarcophagidae are all of the membranous type, with the chorion delicate, transparent, and bearing surface reticulations.
The first‑instar larvae of the parasitic species of Sarcophaga, Blaesoxipha, and other Sarcophaginae have 11 body segments, each of which bears narrow bands of setae at both margins. Anterior spiracles are lacking, and the posterior pair each have two small, circular openings. The larvae of Miltogramma punctatum Meig. and several others have been described and figured in great detail by Thompson (1921) and are representative of the subfamily. They present no special adaptive characters and are of the general muscoid type. For a detailed study of the first‑instar larvae of Sarcophaga, including some parasitic species, please refer Knipling (1936).
The larvae of P. maculata, C. angustifrons, and related species (Thompson, 1920, 1934) differ markedly from those of the Sarcophaginae and are distinctly planidiumlike, with the integument pigmented and armored. The first‑named species is said to have 12 body segments rather than the usual 11. The cuticular armature is well developed and consists of small, rounded protuberances bearing groups of short, heavy spines, one of which is usually larger than the others. In Cirillia, the armature consists of small, dark scales, whereas in Trichogena rubricosa Meig. the somewhat hemispherical processes that bear the sclerotized plates have also what is apparently a sensory organ, which is cylindrical and surmounted by a bristle, at the summit of each. The posterior spiracles of Parafeburia are markedly dorsal in position. The mouth hooks are similar to those of the Sarcophaginae, with two closely appressed lateral teeth rather than the single median one, whereas the latter form is found in Trichogena and Cirillia. There is a single articulation at the juncture of the anterior and intermediate regions. The antennae of Cirillia, instead of being conical, are long and spine‑like and arise from a broad, collar‑like base.
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The second‑instar larvae of the Melanophorinae are quite similar to those of the Sarcophaginae and have the integument delicate, unpigmented, and with few setae. They are most readily distinguished from the preceding instar by the spiracles. The anterior pair is now present; these are fan‑shaped, usually with 5-7 small rays, each of which is surmounted by a small aperture. The posterior spiracles have two vertical parallel slits, of which the inner one is the shorter. In Parafeburia, the anterior spiracles are rudimentary; the posterior spiracles of Styloneuria have only a single slit, and those of Trichogena have three.
The mature larvae of the parasitic species can usually be distinguished from those of scavengerous habit by the reduction in the cuticular processes; the spine bands are narrower or almost absent, and the fleshy segmental spines or processes are lacking. The median depression of the last abdominal segment, characteristic of the family, is usually of smaller size, with the rim more or less smoothly rounded rather than having pronounced fleshy projections. The body tapers markedly cephalad, and the posterior abdominal segments are usually broadest.
The anterior spiracles of Sarcophaga, Brachicoma, and Blaesoxipha have 5-7 rays; there are 14 of these in Agria mamillata, and Parafeburia has 15-18 papillae scattered over the surface of the spiracle. According to Root (1923), who has studied the larval characters of a series of dung‑ and carrion‑inhabiting species of Sarcophaga, the anterior spiracles of these forms have 10-35 rays. The posterior spiracles of all species are set in the median depression of the last abdominal segment, and each has three elongated or occasionally oval slits, which are almost vertical and parallel.
The buccopharyngeal armature has two articulations, and the paired mandibular sclerites are curved and usually sharply pointed, though in Miltogramma punctatum they terminate irregularly and bluntly.
The puparia are usually brown to reddish‑brown in color, though that of Melanophora roralis L. is yellow, and the segmentation is indistinct. The posterior depression of Blaesoxipha is nearly closed by smooth, thick lips; this character serves to distinguish the genus from Sarcophaga. The last abdominal segment of Trichogena is much reduced, forming a tubercle surmounted by the spiracles. The prothoracic cornicles of the pupa do not protrude through the puparial wall. The internal pro‑thoracic spiracles are flattened, are somewhat circular in outline, and have the papillae arranged in double rows, radiating from the center as in Miltogramma and Trichogena, or in groups as in Styloneuria, Cirillia, and Melanophora. There are several hundred papillae in each spiracle of Miltogramma; in Cirillia and Melanophora, they are larger and number only 40 and 30, respectively.