Neurosecretory cells of the nervous system of third-instar larvae of Anastrepha obliqua Macquart, 1835 were located and described histomorphologically. Six groups of neurosecretory cells were identified in the brain and one group in the ventral ganglion. The groups differed in position, cell size and staining characteristics. Four of these groups appear to he active throughout the third instar and three, from the prepupal period.

The length of the entire egg, micropile and vitellus regions of Anastrepha obliqua Macquart, 1835 were measured during all opposition period. Obtained values were compared among them and with oviposition rate. The smallest eggs were produced during the first 35 oviposition days, period where the highest oviposition rate occured. The decrease in egg length was found to be due to a descrease in the vitellus region. Micropile length was found to be pratically constant throughout oviposition. Furthermore, no relationship between maternal age and length was detectable.