Australeon Miller and Stange, 2012

Miller, Robert B. & Stange, Lionel A., 2012, The cave mouth antlions of Australia (Neuroptera: Myrmeleontidae), Insecta Mundi 2012 (250), pp. 1-65 : 40

Australeon Miller and Stange , new genus

Type species: Myrmeleon illustris Gerstaecker , by present designation. Key to species: New and Matsura 1993: 93-94. Further description: New 1985a: 8 (as Callistoleon ).

Biology: Mansell 1988 (pitfall trap with side trenches); New and Matsura 1993 (pitfall traps with side trenches); Matsura and Kitching 1993 (data on trench building).

Diagnosis. Adult: ventral setae of distal tarsomere much shorter than diameter of tarsomere; legs long, hindcoxa longer than five times greatest diameter of coxa; distal tarsomere longer than basal four tarsomeres together; posterior gonapophysis about four times longer than middle diameter.

Description. Adult: body 24-33 mm, forewing 26-35 mm, hindwing 26-35 mm. Structure: antennae widely separated; vertex strongly raised; legs long, hindcoxa longer than five times greatest diameter of coxa; distal tarsomere slightly longer than basal four tarsomeres together; ventral setae much shorter than diameter of tarsomere; tibial spurs about equal in length to pretarsal claws; Banksian lines not indicated; hindwing with four or more presectoral crossveins; forewing with dark brown spots; hindwing weakly falcate, infumate along posterior border; female posterior gonapophysis about four times longer than middle diameter; anterior and lateral gonapophysis broad; male ectoproct without postventral lobe, gonarcus broad, mediuncus well developed.

Larva: labial palpus shorter than basal width of mandible; distance between base of mandible and basal tooth much greater than that between mandibular teeth ( Figure 93); distance between base of mandible and basal tooth much greater than that between mandibular teeth ( Figure 93); mesothoracic spiracle not borne on tubercle; head without dolichasters; mandible with some setae on outer lateral margin as long as or longer than greatest mandibular width ( Figure 98); sternite VIII with pair of inconspicuous submedian teeth near posterior margin; legs long, hindcoxa longer than five times greatest diameter of coxa; pitfall traps with lateral trenches.

Distribution. Only Australia.

Biology. The pitfall characteristics of A. illustris and/or A. manselli have been observed by Mansell (1988), Matsura and Kitching (1993) as well as Miller (pers. obs., 1989). These larvae live in the humid, poorly lighted rear areas of the caves. They often construct side trenches which run downward to the center of the pitfall. The trenches become deeper as the center pitfall is approached. Matsura and Kitching (1993) found that the pitfall traps with trenches were more efficient in prey capture. However, if the larvae were well fed, they tended not to construct the trenches. Miller (1989) also observed Australeon larvae with simple pitfall traps. These larvae are very sensitive to high temperatures and low humidity which can produce death. The abundant ant fauna probably provide much of the food for the antlion larvae.

Discussion. This genus contains two species characterized by the abundant wing markings and previously were included in the genus Callistoleon Banks. However , the type species of Callistoleon , Myrmeleon erythrocephalum Leach , which also has conspicuous spotting of the wings, is otherwise a typical species of Myrmeleon . One diagnostic character of Australeon is that the legs of the larvae are long with the hindcoxa longer than five times greatest diameter of coxa. Australeon differs from Myrmeleon in having the distal tarsomere longer than the other tarsomeres together and also the female posterior gonapophysis is longer than is usually found in Myrmeleon . The larvae have longer legs than those of Myrmeleon with the hindcoxa longer than five times the greatest diameter of the coxa.

Etymology. This genus is restricted to Australia and hence the name is formed by combining Australia and the Greek word leon (lion). Gender masculine.