Gepus invisus Navás, 1912

Badano, Davide, Acevedo, Fernando & Monserrat, Víctor J., 2014, The larvae of Gepus invisus Navás, 1912 and Solter liber Navás, 1912, a comparative description (Neuroptera: Myrmeleontidae), Zootaxa 3785 (1), pp. 87-94 : 88-90

Gepus invisus Navás, 1912

(Figs. 1, 3, 4, 5)

Examined specimens. Tunisia, Bir Soltane: X.2010 (A. Corso leg.), 1 third instar larva reared to adult.

Description. Large antlion larva (Table 1). General coloring (Fig. 1) pale brown with darker markings, ventral side of the body paler with dark brown markings; dorsal side of the head capsule brown with an anterior dark brown marking (Fig. 3), clypeo-labrum dark brown, ventral side of the head pale with a pair of median darker spots (Fig. 4), jaws pale brown, setae of the body mostly black with the exception of the whitish setae covering the clypeo-labrum and mouthparts.

TABLE 1. Average size measurements (mm) of examined 3rd instar larvae of Gepus invisus (1 specimen) and Solter liber (3 specimens). For S. liber , the size range of sclerotized body parts is reported after mean. Abbreviations: body length (excluding mandibles) BL, head length HL, head width HW, mandible length ML, ratio head capsule width/length HW/ HL, ratio mandible length/head capsule length ML/HL.

Head. Head capsule rectangular in shape, longer than wide (Figs. 3, 4); clypeo-labrum concave; antennae thin and relatively short; ocular tubercles small but protruding. Dorsal side of head capsule and margin of the labrum covered with white dolichasters. Mandibles relatively robust, shorter than the head capsule (Fig. 3); the median tooth is the largest and it is closer to apical tooth than to the basal tooth, distance between the base of the mandible and the basal tooth similar to that between the basal and apical teeth; 4–5 stout setae between the base of the mandible and the basal tooth, 2–3 setae between the basal and median teeth, 1 seta between the median and apical teeth; dorsal side of mandible sparsely covered with very short black setae, ventral side of the mandible with very short setae both internally and externally to the maxilla, external margin of the mandible equipped with sparse setae longer toward the base; labial palpi covered with white dolichasters (Fig. 4).

FIGURE 1. Gepus invisus (Navás, 1912) , 3rd instar larva, live specimen ( Tunisia: Bir Soltane). A: dorsal view, B: ventral view, C: lateral view.

Thorax. Pronotum covered with whitish dolichasters. Mesothoracic spiracle sessile, pale brown. Mesothoracic setiferous processes sub-pedunculated, not prominent (Fig. 3).

Legs. Pale, covered with black setae; metathoracic legs with a fringe of setae.

Abdomen. Covered with dark setae on the margins; VIII sternite with inconspicuous odontoid processes; IX sternite with not prominent rastra each bearing 4 relatively long and thin digging setae of which the internal pairs are shorter (Fig. 5).

Ecological notes. This species is associated with desert biotopes. The examined specimen was collected under a stone near dunes at Bir Soltane, in the Tunisian sandy desert. Stange (2004) reports findings of larvae of the same genus in Tunisian sand dunes.

Behavioral notes. The larva of Gepus is a sit-and-wait predator, not building pit-traps and able to move both forward and backward.