Immature Stages of Therevidae
Detailed information on immature stages of Therevidae is being acquired. However, Clausen (1940) noted that the larvae live in sandy soil and are predaceous ;on earthworms and various soft-bodied insects. The larvae of Phycus brunneus Wied. occurring in bat dung in India are believed to feed on dermestid larvae Isaac 1925). But Goetz (1932) considered that the supposed predaceous habit of the larvae was still questionable.
The immature stages are similar to Asilidae. The 1st instar larvae are vermiform, with 20 apparent segments, due to Aintersegments@ between the first 6 true segments of the abdomen. Prothoracic and caudal spiracles are present. Mature larvae of Psilocephala sequa Wlk. (Bhatia 1934) are also elongated and bear spiracles at the posterior margin of the first thoracic segment and at the anterior margin of the 4th segment from the end of the abdomen. Pupae have heavily sclerotized processes on the antennal sheath and at the base of each wing sheath. The abdominal segments each bear a ring of long spines at the posterior margin, and the last segment is produced into a pair of large, heavily sclerotized processes.
References: Please refer to <biology.ref.htm>
[Additional references may be found at: MELVYL Library]