Observations of the third instar larva and puparium of Chrysomya bezziana (Diptera: Calliphoridae).

Observations on the ultrastructure of the third instar larva and puparium of the Old World screw-worm fly, Chrysomya bezziana, are presented utilizing both light microscopy (LM) and scanning electron microscopy (SEM). Results of this study indicate that the shape of the intersegmental spines between the pro- and mesothorax markedly differ from other blow fly species (Chrysomya megacephala, Chrysomya rufifacies, Chrysomya nigripes, Lucilia cuprina) in being broad-based with sharp recurved tips. Other characters such as the posterior spiracles, number of papillae on the anterior spiracles, oral grooves, and posterior spiracular hairs also differ. The strong and robust mouthhooks may explain the ability of larvae to penetrate deeply into human tissues. Perforated sieve plates covered with antler-like projections were observed within the anterior spiracles of the puparium of C. bezziana. The posterior spiracular discs each bear three spiracular slits with approximately 2-microm wide openings that were viewed either open or closed by a membrane underneath. This study expands our knowledge of the fine details of the external morphology of both the third instar larva and puparium of C. bezziana, which is an obligatory myiasis-producing species in many regions. A key to differentiate the third instar of C. bezziana from other blow flies in Thailand is given.

Surface ultrastructure of the puparia of the blow fly, Lucilia cuprina (Diptera: Calliphoridae), and flesh fly, Liosarcophaga dux (Diptera: Sarcophagidae).

Surface ultrastructure of the puparia of the blow fly, Lucilia cuprina, and flesh fly, Liosarcophaga dux, are presented utilizing scanning electron microscopy (SEM). Emphasis was focused on characteristic features of the puparia that could be used for differentiation from other forensically important fly species. The puparium of L. cuprina typically measures 6.2+/-0.2 mm in length and 2.3+/-0.1 mm in width. Each anterior spiracle contains a single row of 5-7 papillae. The intersegmental spines between the prothorax and mesothorax are triangular with constricted tips. A clustered bubble membrane, comprising about 30 mammillate structures, is positioned dorsolaterally on each side of the first abdominal segment in young puparia but is replaced by short, tubular respiratory horns in aged puparia. The posterior end of the puparium is broadly truncate and bears a pair of medially positioned posterior spiracles that each contains three straight spiracular slits. The puparium of L. dux is larger in comparison to L. cuprina and typically measures 9.9+/-0.3 mm in length and 3.8+/-0.2 mm in width. An anterior spiracle of this species contains 14-17 papillae. The intersegmental spines between the prothorax and mesothorax are broad and triangular. A convoluted structure of unknown function was observed at the dorsolateral edge of segments 5-11. In L. dux, the caudal segment of the puparium is slightly tapered and abruptly truncated and contains a pair of posterior spiracles that are located within a deep concavity in the terminal end. Each posterior spiracular disc appears D-shaped, with a pronounced medial projection and three vertically oriented long, narrow spiracular slits. The anatomical features presented herein may be useful for identification of fly puparia of these two species in future forensic entomological investigations.

The first documented forensic entomology case in Thailand.

The forensic entomology case described herein is the first such case documented in Thailand. A mummified corpse of a 32-yr-old man was discovered in a forested habitat, with the larvae of six species of flies (Diptera) found in association with the corpse at the time of its discovery, i.e., those of Hydrotaea (=Ophyra) spinigera Stein (family Muscidae), Piophila casei (L.) (family Piophilidae), Megaselia scalaris (Loew) (family Phoridae), Sagus sp. (family Stratiomyidae), and larvae of two unidenitified flesh fly species (family Sarcophagidae). The presence and age of the larval specimens of P. casei, M. scalaris, and H. spinigera gave entomological evidence that the postmortem interval for the corpse was 3-6 mo. This report also documets some of the forensically important fly species that occur in Thailand.

Scanning electron microscopy of the third-instar Piophila casei (Diptera: Piophilidae), a fly species of forensic importance.

The morphology of third-instar Piophila casei (L.) is described by means of scanning electron microscopy. Features of the anterior cephalic region and creeping welts that are used in larval skipping and creeping, respectively, are highlighted. Morphological features classically used for larval identification are also illustrated.

Surface ultrastructure of the third-instar larvae of Hydrotaea spinigera Stein (Diptera: Muscidae), a fly species of forensic importance.

The surface ultrastructure of third-instar larvae of Hydrotaea (= Ophyra) spinigera Stein was observed with scanning electron microscopy. The number of papillae in each anterior spiracle ranges from 5-7. Abdominal segments 4-12 possess ventral welts. Each posterior spiracular disc bears 3 nearly straight slits, with the lower and middle slits closer together than the middle and upper slits. Although the larvae of H. spinigera are generally similar to two other closely-related species in Thailand, Hydrotaea (= Ophyra) leucostoma (Wiedemann) and Hydrotaea (= Ophyra) chalcogaster (Wiedemann), some of the morphological features can help in differentiating these species, thus allowing more accurate identification of species of fly larvae in forensic investigation.