Description of immature stages of Tephritis stigmatica (Coquillett) (Diptera: Tephritidae)

The pre-imaginal stages of Tephritis stigmatica (Coquillett) are described. Tephritis stigmatica is an oligophagous, multivoltine, facultatively axillary-bud-gall-forming and florivorous tephritid associated with Senecio spp. (Asteraceae) in southern California. The egg, first-, second-, and third-instar larvae and puparium are described and figured, and selected characteristics of these stages are compared with those of other southern California Tephritis. The egg of T. stigmatica is covered by a smooth, membraneous sheath of unknown function. The descriptions of the first, second, and third instars are the most complete reported to date for the genus Tephritis. The integumental petals of all three instars are found in medial and lateral positions on the gnathocephalon and increase in numbers from the first to the last instar. The most lateral integumental petal is fused with the stomal sense organ in the first instar. The anterior spiracle has four or five papillae in the second instar, and four papillae in the third instar. The pairs of stelex sensilla surrounding the posterior spiracular plates increase in number from the first to the second instar, and retain the same number and locations, but include two pairs of verruciform sensilla dorsally and laterally in the third instar. The lateral spiracular complexes of the metathorax and first abdominal segment of the second and third instars are described and pictured. The lateral spiracles of the third instar uniquely are prominent on raised peritremes, unlike the second instar, in which they are difficult to locate, as in most other tephritine larvae.