Xantholeon Tillyard, 1916

Miller, Robert B. & Stange, Lionel A., 2012, The cave mouth antlions of Australia (Neuroptera: Myrmeleontidae), Insecta Mundi 2012 (250), pp. 1-65 : 29-30

Xantholeon Tillyard

Xantholeon Tillyard 1916: 61 . Type species: Xantholeon helmsi Tillyard , by original designation. = Cataleon Navás 1933: 34 . Type species: Cataleon gratiosus Navás , by original designation (after New

1985c: 10).

Further description: New 1985c: 10.

Diagnosis. Adult: pale brown coloration; antenna long with usually well developed club; wings tapered, sometimes slightly falcate; no Banksian lines; female anterior gonapophyses absent; female posterior gonapophyses moderately long, slender; female ectoproct and lateral gonapophyses with thickened setae; male sternite IX broad and rounded; male parameres angled anteriorly, not hooked; male ectoproct without postventral lobe..

Description. Adult: body 20-24 mm, forewing 23-32 mm, hindwing 24-31 mm. Coloration: pale brown to yellowish colored species. Structure: antenna long with well developed club; wings tapered, sometimes slightly falcate, without Banksian lines; forewing about as long as the hindwing which is longer than abdomen; forewing radial sector arises beyond cubital fork; forewing CuP+1A reaches to posterior wing border opposite or before origin of radial sector; forewing vein 2A either strongly angled and connected to vein 1A by short crossvein or is curved toward hind margin; hindwing radial sector arises basal to medial fork; legs slender; tibial spurs longer than basal tarsomere; male ectoproct broad and rounded; gonarcus various; parameres dorsally angled anteriorly, not strongly hooked; female terminalia without anterior gonapophysis, posterior gonapophysis moderately long and slender; pregenital plate small.

Distribution: only Australia.

Biology. The larvae are found in Zone 4B in the back of the cave in relatively shallow sand so that they can anchor themselves to the bedrock. The larvae are covered with sand or dust except usually for protruding mandibles and may move about from time to time. In this zone, light is lower, air currents are less and the humidity is usually higher. They co-exist with larger larvae of Eophanes falcatus which probably feed on them as well as the less common Escura nigrosignata .

Discussion. There are ten species currently recognized in this genus, eight of which were reared from larvae. All the species are pale colored and probably all of the larvae live under rock overhangs or cave mouths. There are two groups of species and are unusual in the tribe in that some species have the strongly angled forewing 2A that is characteristic in the tribe but a few species (helmsi group) have the forewing vein 2A curved toward the hind margin. The helmsi group consists of five species ( X. helmsi , X. manselli , X. kakadu , X. pallens , and X. pentlandensis ). The helmsi group has the forewing vein 2A curved toward hind margin ( Figure 55) and the hind basitarsus is at least as one-half as long as the distal tarsomere ( Figure 56). The lineatus group has forewing vein 2A strongly angled and connected to vein 1A by a short crossvein ( Figure 52) and the hind basitarsus is less than one half the length of the distal tarsomere ( Figure 50). This group includes X. cavernicolus n. sp., X. montanus New, X. lineatus New, X. newi n. sp., and X. xadnus New. The larvae are all morphological similar with minor differences in markings and differ from the similar Stenoleon by their shorter antenna.