Diplectrona inermis (Banks)

Wells, Alice & Contents, Arturs Neboiss Table Of, 2018, Australian Diplectroninae reviewed (Insecta: Trichoptera), with description of 21 new species, most referred to a new genus, Zootaxa 4415 (1), pp. 1-44: 8-10

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Diplectrona inermis (Banks)


Diplectrona inermis (Banks)  

( Figs 1–9 View FIGURES 1–9 , 13, 20, 26, 29, 31 View FIGURES 17–31 , 35–37)

Sciops inermis Banks 1939   , 494.

Diplectrona inermis   ; Neboiss 1986, 218.

Material examined. Holotype ♂, Diplectrona inermis   , New South Wales, Wentworth Falls, Blue Mtns , 3.i.1932 ( ANIC, ex MCZ 220889)   ; paratype ♂, data as for holotype [ MCZ 22089 View Materials ]. Queensland: 1♂ 2♀, Branch Creek, Brisbane Riv. Catchment , 26°52'S 152°41'E, 15.xii.1992. New South Wales: 6♂ 1♀ GoogleMaps   , NSW, Katoomba Falls and stream, 6.i.1955, T.E.W. [TRI-39840]; 1♂ 1♀, Cascades, Katoomba, 12.ii.1961, C.N. & A.S. Smithers; 2♂ 1♀, Minnamurra Falls, W of Kiama, 25.iii.1973, A. Neboiss; 1♂, Wentworth Falls , 23.xii.1977, A. Neboiss [TRI- 39414]; 8♂ 1♀, Leura, ‘ Bridle Vale’, 27.xii.1978, A. Wells [PT-1092, PT-1032, PT-1057 ♀; TRI-39418, TRI- 39411, TRI-39397]; 1♂ [TRI-39864], Ebor Falls , 12.xi.1983, G. Theischinger; 1♂, Leura, Lyre Bird Dell, 12.xii.1984, A. Wells [TRI-39425]; 18♂ 2♀, Blue Mtns, Leura Cascades, 12.xii.1984, A. Wells [TRI-39431, TRI- 39421]; 3♂ 1♀, Leura, below Falls, 13.xii.1984, A. Wells [TRI-39430]; 1♂, Royal Nat Pk 2.x.1985, A. Neboiss [TRI-39937]; 1♂, Barrington Tops, Upper Williams R., 26.01[i]. 1987, 550 m, D.J. Bickel; 1♂   , NSW, Chichester State Forest, Jerusalem Creek, 26.xii.2000, A. Wells ( ANIC). Victoria: 2♂, Wilson’s Promontory, Waterloo Bay , 25.i.1958, N. Dobrotworsky [PT-1011]; 1♂, Tarra Valley Nat Park, 8.xii.1984, A. Neboiss.  

Diagnosis. Distinguished from D. tasmanica   , D. serrula   , and D. castanea   by the longer harpagones on the coxopodites of the gonopods, and the presence of discrete sclerotised spines on the phallic apparatus, and from the closely similar D. spinata   by having 2 pairs of spines subequal and laterally directed in contrast to D. spinata   which has a single pair of prominent, dorsally curved spines with short spines at their bases.

Description (revised). Length of each forewing: ♂, 6.0–7.0 mm (n = 10), ♀, 6.8–8.0 mm (n = 5).

Male. Abdominal reticulate-walled internal sacs about 1.0 to 1.5x segment length ( Fig. 29 View FIGURES 17–31 ); lateral filaments on sternite V almost length of segment ( Fig. 31 View FIGURES 17–31 ).

Genitalia ( Figs 3–9 View FIGURES 1–9 , 35–37): Abdominal segment IX not deeply concave laterally, dorsally fused partially with tergite X; midlateral margin projecting posterodorsad in triangular process, in lateral view appearing as triangular ‘phallic guide’; tergite X well developed, rounded apically, in dorsal view shallowly cleft apicomedially; gonopods slender, elongate, each with coxopodite swollen towards apex, length about 4x maximum width, harpago almost 1/3 length of coxopodite, simple, curved mesad, tapered toward apex; phallic apparatus stout, 2 pairs of discrete sclerotised spines laterally, single spine midventrally.

Female. Abdominal sternite VIII in form of pair of subquadrate ventral plates, mesodistal angles broadly rounded, apicolateral angles produced slightly, rounded ( Fig. 13 View FIGURES 10–16 ); segment IX basally with transverse opening to sclerotic cavity; on segment X cerci and apical papillae short compared to those of Austropsyche   species.

Distribution. Found from central Victoria through eastern New South Wales to south-eastern Queensland.

Remarks. The two Banks’ species, D. inermis   and D. spinata   , were described from intact dried specimens, the result being that the original illustrations are very deficient. In redescribing Banks’ types for Philippines’ species of Hydropsychinae   and Diplectroninae   , Mey (1997) commented that they are ‘… mostly … crude figures of wing venation and genitalic appendages of dry specimens’. Ross and Morse (unpublished MS, from correspondence between Morse and Ross dated in 1975), macerated Banks' Australian Trichoptera   types (including Sciops spinata   and S. inermis   ) and prepared new diagnoses (effectively descriptions) and illustrations. Once macerated, it was evident that males of both species have phallic spines (recognised by Ross and Morse as endothecal spines), the major distinguishing features being the size and arrangement in each species. In describing D. cognata, Kimmins (1953)   commented that it may be D. inermis   , but that Banks (1939) had not mentioned the spines. Here, however, D. cognata   is synonymised with D. spinata   , although, perhaps puzzlingly, the holotypes of D. inermis   and D. cognata   are both from the same locality.

In many of the available specimens of D. inermis   and D. spinata   , the phallic spines vary in length and extent of curvature and often are not clearly visible, which makes separation of the two species difficult. Mosely & Kimmins (1953) distinguished Diplectrona spinata   and D. inermis   by the length of the discoidal cell in each forewing, but this characteristic was not confirmed in this study (compare Figs 1 View FIGURES 1–9 and 23 View FIGURES 17–31 ). Diplectrona inermis   appears to display considerable variability across its range.


Australian National Insect Collection


Museum of Comparative Zoology


Royal Botanic Gardens, National Herbarium of New South Wales














Diplectrona inermis (Banks)

Wells, Alice & Contents, Arturs Neboiss Table Of 2018

Sciops inermis

Banks 1939