Sensilla trichodea
The adult labial palps have a relatively small number of sensilla trichodea, with only one subtype, ST II, which is more abundant and is found in all segments of the labial palpus in both sexes. It has a blunt apex, a V-shaped pattern in the epidermal wall and a loose basal fossa (Fig. 4).
There was no significant difference in the number of labial palpus ST II between males and females (Fig. 3), but the basal width of ST II was significantly wider in females than in males.
Sensilla placodea
The sensilla placodea (SP) of brown-spotted G. cantor was long and lamella-plate-shaped with a loose basal fossa and smooth epidermal walls (Figs. 4, 6), and in adults, the labial palpus and mandibular palpus sensilla placodea were distributed on the outer side of the terminal segment.
Females had significantly more SP than males in both labial palps (♀ = 17.00 ± 0.32, ♂ = 12.80 ± 0.58, t = 6.33, P < 0.01) (Fig. 2), but the length of the SP of the labial palpus was significantly longer in males than in females (Table 4).