Zalea horningi (Harrison)

McAlpine, D. K., 2007, The Surge Flies (Diptera: Canacidae: Zaleinae) of Australasia and Notes on Tethinid-Canacid Morphology and Relationships, Records of the Australian Museum 59 (1), pp. 27-64 : 53-54

Zalea horningi (Harrison)

Figs 20, 62–65

Tethina horningi Harrison, 1976: 143 , fig. 3.

Zalea horningi (Harrison) .–D. McAlpine, 1985: 82.

Material examined. HOLOTYPE?, New Zealand: Seal Cove , Snares Islands, 2.1.1972, D.S.H. ( NZAC). Dry-mounted on card-point, postabdomen now placed in microvial attached to pin . PARATYPES. As listed by Harrison. I examined 2??, 2!! from NZAC in 1982 but details of the postabdomens were not then studied.

Other material (localities only). South Island: Kaikoura Peninsula ( AM); Sumner, near Christchurch ( AM, BM); Laverick’s Bay, near Akaroa ( AM, NZAC); Otanerito Bay, near Akaroa ( AM, NZAC); Pilot Beach, Otago Peninsula ( USNM).

Supplementary description

Very similar to Z. johnsi and agreeing with description of that species except as indicated below.

Coloration. Abdomen of female: paired sclerites of tergite 7 dull yellowish, black anteriorly, dull grey on small posterior zone.

Head. Postvertical bristles small, convergent.

Thorax. Wing: cell-4 index = 0.50 (holotype), 0.53–0.59 ( South Island material) .

Abdomen. Male: anterior surstylus, almost straight but slightly incurved, rounded and compressed apically, with short setulae mainly on inner surface, with no particularly developed setulae on posterior surface, extensively microtrichose, mainly on inner surface of distal half; posterior surstylus broadly rounded apically, with at most only slight posterior basal incision, microtrichose on large part of inner and outer surfaces, with few small setulae on outer surface, with larger setulae in inner surface, of which a few more basal ones are particularly large; each anterior aedeagal papilla not smooth and evenly tapering as in Z. johnsi , but with zone of transverse ridges near mid-length, and slender, obtuse, roughly pustulose apical part; posterior papilla with many short, transverse surface ridges, slightly narrowed well before apex to form somewhat transversely compressed distal part with anterior concavity and rather thick rounded apex; distiphallus a little broader distally than in Z. johnsi , with less finely pointed, slightly irregularly incised apical part. Female: sternites generally as in Z. johnsi ; sternites 2 to 6 all divided in two or almost so; tergite 7 ( Fig. 65) very deeply divided, somewhat like that of Z. dayi but with more elongate anterior apodeme.

Distribution. New Zealand: South Island; Snares Islands.

Notes

The key to species and the above comparative description gives all the points of difference from Z. johnsi that I am able to confirm. The convergent postvertical bristles of this species provide a remarkably consistent difference from Z. johnsi , and associate Z. horningi with the four species Z. lithax , Z. mathisi , Z. uda , and Z. ohauorae , which are recorded at present only from North Island vicinity.

The above description of postabdominal characters is based mainly on South Island specimens. I have examined the epandrium and surstyli of the holotype which resemble those of South Island material. As further dissection of this specimen may have proved destructive, details of the hypandrium and aedeagus have not been checked for the Snares Island population.