ABSTRACT In central Chile, Rhagoletis brncici and R. conversa, can be found in sympatry, associated with the fruit of their native host plants: Solanum tomatillo and S. nigrum (Solanaceae), respectively. Third-stage larvae must emerge from its host in search of pupation sites, and during this period larvae must find an appropriate pupation microhabitat while avoiding predation and adverse abiotic factors. In this study, we explored whether these sympatric species differ in terms of the timing of their larval exit from the host fruit in search of pupation sites. Field-collected fruits from host plants were checked daily for larval emergence, within 24 h, under laboratory conditions, in order to determine the time of the event. We found that these species differed significantly in their diel larval emergence. For R. brncici, most larvae left the host fruit between late evening and past midnight, meanwhile larvae from R. conversa concentrated their peak of emergence near midnight and early morning. We discuss these findings in terms of the ecological and evolutionary implications of the temporal separation of larval emergence regarding the use of pupation sites, abiotic stress and risk of predation for these sympatric species.

In the present study, the morphology, color pattern, chromosomal complement and aspects of meiosis in natural populations at the borders of the distributions of Mepraia gajardoi Frías et al and Mepraia spinolai (Porter) are described. The males of these bordering populations are brachypterous or macropterous, while females are always micropterous. Morphological and cytogenetic data indicated that the populations that border the distributions of M. gajardoi and M. spinolai, belong to a different species of parapatric origin.

A morfologia da larva do terceiro ínstar de Anastrepha leptozona Hendel é descrita. São analisados, em microscopia de luz e de varredura, o complexo antenomaxilar, as margens da abertura oral, o bordo, o órgão oral, o esqueleto cefalofaríngeo, os espiráculos anterior e posterior e o segmento caudal. As larvas do terceiro ínstar de A. leptozona têm um "esclerito ventral" abaixo do esclerito faríngeo, o qual é caracterizado pela primeira vez em espécies de Anastrepha.

The morphology of the third-instar larva of Anastrepha leptozona Hendel is characterized using optical and scanning electron microscopy. The antennomaxillary complex, oral ridges, labium, stomal sensory organ, cephalopharyngeal skeleton, anterior and posterior spiracles and caudal segment are described and illustrated. Mature larvae of A. leptozona present a "ventral sclerite" below the pharyngeal sclerite which is characterized for the first time in Anastrepha species.

The histology and morphology of the reproductive system of females of Rhagoletis conversa (Brèthes) and Rhagoletis nova (Schiner) were studied. These species parasitize wild and cultivated Solanaceae respectively. Adult females of both species were collected in natural populations in the Central Zone of Chile. In order to study the development of ovaries the females collected were sacrificed at different ages. Once obtained, ovaries were preparedfor optical microscopy by using histological and squash standard techniques. Results show that within each one of ovarioles it can be observed follicles arranged in line and showing different stages of maduration. It can be described about 6 follicle stages in the ovarioles studied. Ovaries of both species show a very similar structure. However, females of Rhagoletis nova show an ovipositor wider than R. conversa. The number of ovarioles of R. nova is also higher than in R. conversa.