Background: Accurate identification of the larval stages of Wohlfahrtia nuba, a flesh fly species within the Sarcophagidae family, is crucial in forensic and medical entomology. This species may contribute to estimating the postmortem interval (PMI) and is associated with causing myiasis in livestock and humans. The insufficient data regarding the morphology of the immature stages of W. nuba hinders the taxonomic identification of this species&rsquo; larvae in carcasses without raising adults. Therefore, this study provides a comprehensive examination of the morphological characteristics of three instars of W. nuba larvae using light microscopy. 
 
Methods: It includes an examination of the cephalopharyngeal skeleton, pseudocephalon, antennal complex, oral ridges, anterior spiracles and their papillae number and arrangement, thorax and abdomen spinulation, number and distribution of papillae around the entrance of the spiracular cavity and posterior spiracles. 
 
Result: The present study&rsquo;s findings demonstrate the distinct morphological characteristics that differentiate the three larval instars, facilitating accurate identification and developmental staging. The three larval stages have two curved mouth hooks. A large median hook is absent. The labrum is a reduced structure exhibiting four highly sclerotized teeth between the mouth hooks. The dorsal arch is short, curved and does not extend to the parastomal sclerite. The anterior spiracles, located laterally on the first thoracic segment, exhibited variability in the number of papillae across the three instar larvae. The first larval instar exhibited a total of eight papillae, which increased to 10 in the second instar and reached 11 in the third instar. These papillae are arranged in a row resembling an arch. The spines encircling the cephalic collar are thin and set into 6-7 rows, separating the first segments of the thorax. The posterior spiracle contains two incomplete peritremes hidden in a deep cavity. It is characterized by a single aperture divided at its upper section and shielded by thin hair-like structures during the first larval instar. Each incomplete peritreme contained two slits for the second larval instar and three slits for the third larval instar. The peritreme lacks a ventral arch and the button is not easily noticeable. A ring of 12 cuticular papillae encircles the anal cavity. These data add new morphological features to differentiate between W. nuba larvae in clinical and forensic contexts. This will help with taxonomic and forensic species identification studies and benefit farmers and veterinarians. 
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Morphological Description of the Three Larval Instars of Wohlfahrtia nuba (Diptera: Sarcophagidae)

Background: Forensic entomology utilizes insects for legal and criminal investigations, particularly in determining the time of death when traditional medical parameters become ineffective after 72 h. Insects play a crucial role in Post-Mortem Interval (PMI) estimation and provide insight into crime scene events. 
 
Methods: This study focused on the collection and molecular identification of forensic insects in Jeddah, Saudi Arabia. Rabbit carcasses were used as human analogs and were placed in specialized cages across five locations. Insects were collected twice daily for two weeks and identified based on their morphological and molecular characteristics. DNA extraction, polymerase chain reaction (PCR)and sequencing were used for genetic analysis. 
 
Result: Phylogenetic analysis revealed significant genetic similarities among the collected species, indicating low genetic diversity and a stable population structure. The key species identified were Sarcophaga dux, Wohlfahrtia nuba, Sarcophaga harpax, Chrysomya albiceps, Chrysomya megacephala, Chrysomya marginalis, Atherigona orientalis, Musca domestica and Hydrotaea capensis. These findings support the use of genetic analysis for accurate species identification in forensics. Additionally, this study highlights the potential impact of climate change on insect populations, suggesting future research directions in forensic entomology. This study contributes to the understanding of forensic insect ecology in the Kingdom of Saudi Arabia and enhances forensic investigation methods.

Morphological Description of the Three Larval Instars of Wohlfahrtia nuba (Diptera: Sarcophagidae)

Molecular Identification of Forensic Insects Collected from Jeddah, Saudi Arabia