Immature Stages of Pipunculidae
There were only two larval instars of A. spuria recorded by Keilin & Thompson (1915a), the second having all the characteristics of a normal 3rd instar cyclorrhaphous larva. The first instar is 1.0 mm. long and a bit elongate. It bears a vesicle-like organ at the posterior end of the body. The skin bears neither sensory spines nor setae, and no tracheal system is distinguishable until late in the stage when the lateral trunks fill with air. The second instar, or mature larva, is robust and oval in outline, with the caudal vesicle still present although reduced in size. The anterior spiracles are elevated, and each has 4-5 openings. The posterior spiracles, each with three openings, are also elevated and are situated at the lateral margins of a large, black, heavily sclerotized peristigmatic plate. This single plate, on which both spiracles are borne, is typical of the family.
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In most cases the advanced 1st instar Ateleneura larva lies with its head directed toward the host's thorax, but after the molt the position is reversed, the head being near the tip of the abdomen and the caudal extremity at the juncture of the abdomen and thorax. Parasitized leafhoppers containing nearly mature Pipunculus larvae may be easily recognized by the distended condition of the abdomen. The larva emerges from the Typhlocyba nymph or adult through an opening made between two segments of the abdomen and enters the soil to pupate. In Pipunculus sp. the larvae were always found by Perkins (1905e) to lie with the head directed frontwards, and emergence was through an opening at the juncture of the thorax and abdomen. In P. xanthocnemis Perk, parasitic in Liburnia, the emergence hole is in the mid-dorsal abdominal area. The mature larvae of P. annulifemur Brun. can jump similar to fruit fly larvae (Subramaniam 1922). Although most species pupate in soil, some like P. cinerascens Perk. form puparia on foliage. The larva of P. xanthocerus Kow. differs in having the integument heavily spinose rather than smooth, a trait that persists in the puparium.
Puparia of Pipunculidae are broadly oblong in outline, often with a granular or rugulose sculpturing, and are red, black or brown in color. The prothoracic cornicles are very small in some species, and can barely be seen projecting through the puparial wall. In other species, such as P. cinerascens, they are borne at the apices of very large conical processes. The posterior stigmatic area is rounded in some species and depressed in others, with the spiracles borne at the lateral margins. Each spiracles usually has three openings, although there may be two in some species and in others only one. The entire anterior portion of the puparium is completely or partly forced off in two parts, the dorsal one usually bearing the prothoracic cornicles, at eclosion. The transverse line of fracture is just behind the anterior margin of the 2nd abdominal segment (Clausen 1940/62). In Chalarus and Verallia, there is a modification in the manner of emergence from the puparium. The two anterior plates, which are forced off, are broken further, the upper one into three parts and the lower into two (Lundbeck 1922). In this way five pieces are detached from the puparium compared to only two in Pipunculus. The prothoracic cornicles occur along the line of fracture and are not a part of the median dorsal plate. The relation between the five parts and the lines of fracture were shown by De Meijere (1917) for an undetermined species.
Swezey (1936) reported on the duration of the life cycle for several species of Pipunculus. The combined egg and larval stages last 40 days and the pupal stage about one month. The pupal stage is completed in 14-19 days in P. annulifemur.
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