Insects have a large number of sensory organs (sensilla) on their mouth parts, which play crucial roles in the host acceptance and localization processes as well as in detecting environmental stimuli. Sensilla, therefore, play a crucial part in the location, selection, and acceptance of a potential host by parasitoid hosts. Based on the types, numbers, and distributions of sensory organs, one can deduce how they function. These biological parameters have been tested. In this work, the external sensilla on the mouth portions of Leptocype invasa (Fisher and La Salle) and Ophelimus maskelli (Ashmead) were described (Hymenoptera: Chalcidoidea: Eulophidae). In Egypt, these two inducer gall species primarily affected Eucalyptus camaldulensis. Using electron scanning microscopy, the sensilla were categorised based on their size, distribution, and shape; some may even have sense organs visible. On the mouthparts of L. invasa and O. maskelli, eight different types of sensilla were found, and depending on their length and distribution, some of them can be further split into numerous categories. Sensilla came in 16 different varieties overall. In the current study, O. maskelli had more sensilla overall on oral parts than L. invasa, with 109 sensilla on O. maskelli compared to more than 95 on L. invasa along the mouthparts. Results from the examined biological characteristics were explained by qualitative and quantitative differences in the type of sensilla on both species' mouthparts, favouring O. maskelli. These findings tend to imply that O. maskelli is a more advantageous rival that could supplant L. invasa. Despite the two species' similar body sizes, O. maskelli was smaller than L. invasa. However, O. maskelli mouth showed more sensilla types overall than L. invasa.