Wesche, W. 1910. On the new tipulid subfamily Ceratocheilinae. Journal of the Linnean Society of London, Zoology 30: 358.
Toxorhina is one of three Limoniinae genera (Elephantomyia and Helius) that show an elongation of the rostrum to a length that equals or more commonly greatly exceeds the length of the remaining head. In overall appearance and wing venation the three genera are quite similar and easily mistaken. Toxorhina is separated from the other two genera based on the deeply divided and bifid setae of the legs (singular in Elephantomyia and Helius and the remaining Limoniinae).
The two subgenera of Toxorhina (Toxorhina and Ceratocheilus) are divided on the basis of the Radial sector of the wing, with Toxorhina having one branch of Rs to with wing margin and Ceratocheilus having two branches of Rs to the wing margin.
Head: anterior vertex not expanded, width variable; rostrum elongate, from 2 times head to greater than 10 times its length; maxillary palps at apex of rostrum, small, palpomeres subequal. Antennae: Variable number of articles (13-17) because of compression and fusion of basal segments, typically 14 articles in male and 15-17 in female; basal antennomeres compressed, becoming more cylindrical apically.
Wing: Subhyline to lightly suffused; stigma present or absent; anal angle of wing present. Wing venation: Sc1 removed from Sc2, ending near origin of Rs; rarely Sc2 absent; R1 short, straight to wing margin; R2 crossvein absent; one branch of Rs (R4+5) attaining wing margin; two Medial veins (M1+2, M3)attaining wing margin; cell dm absent, rarely present; CuA crossvein near split of M; two Cubital veins (CuA1, CuA2) attaining wing margin; two Anal veins (A1, A2) attaining wing margin.
Legs: setae of legs deeply divided and bifid.
Male hypopygium: 9th tergite (9t) and sternite (9s) fused. Mesoventral lobe of gonocoxite absent or weakly present. Gonocoxite with a basal interbase. Gonostylus bifid or singular; dorsal style a sclerotized rod, narrowed at its apex; ventral style sclerotized rod that is variably produced, typically stouter than dorsal style but subequal in size, its tip bifid to varying degrees. Aedeagus bifid, length variable. Proctriger simple, without modification.
The 76 species of Toxorhina (Ceratocheilus) are strongly an equatorial group, being represented in the Neotropical (11 species), Oriental (14 species), Afrotropical (22 species), an d Australian/Oceanic (24 species) Regions. No species are known from the Holarctic Region.
The larval habitat of this subgenus is unknown, but Toxorhina (Toxorhina) is thought to inhabit rotten wood found in saturated soils of swamps (Alexander 1964).
