Key to species of Imbecilla (males)

Note: Imbecilla viridus Ahmed, 1979, here considered a species incertae sedis within Erythroneurini, is not included in the key.

1 Style apex with second extension little or no longer than distance between mesal and lateral angles of first extension...... 2

- Style apex with second extension distinctly longer than distance between mesal and lateral angles of first extension (Figs 10g, 11h)................................................................................................ 8

2 Style apex with second extension very short and broad, lamelliform.......................... I. imbecilla (Linnavuori)

- Style apex with second extension acutely produced.......................................................... 3

3 Style apex with second extension as long as or slightly longer than distance between mesal and lateral angles of first extension................................................................................................ 4

- Style apex with second extension shorter than distance between mesal and lateral angles of first extension............... 7

4 Style with second extension strongly curved; aedeagal shaft expanded near midlength with lateral flange in posterior view, basal processes not extended to level of shaft apex........................................................... 5

- Style with second extension straight or nearly so; aedeagal shaft slender in posterior view, basal processes extended to or well beyond shaft apex..................................................................................... 6

5 Pygofer dorsal appendage without additional process, aedeagal shaft in posterior view with lateral flanges angulate and smooth, paired basal processes robust and well separated from shaft in lateral view, apical processes very short...... I. lubiae (China)

- Pygofer dorsal appendage with additional process, aedeagal shaft in posterior view with lateral flanges rounded and serrate, paired basal processes slender and close to shaft in lateral view, apical processes long............ I. igneusa Dworakowska

6 Pygofer dorsal appendage with two or three angulate distal projections; basal processes of aedeagus well separated and divergent from each other................................................................... I. tera Dworakowska

- Pygofer dorsal appendage terminating in a single point; basal processes of aedeagus crossing each other near base........................................................................................ I. cretinica Dworakowska

7 Aedeagal shaft in lateral view bent anterodorsad at acute angle near midlength, with preapical angulate projection on dorsal surface........................................................................... I. cinerea Dworakowska

- Aedeagal shaft in lateral view curved dorsad from base then slightly arcuate, without preapical projection on dorsal surface................................................................................... I. variata Dworakowska

8 Style apex with second extension evenly recurved, apex oriented basolaterad...................................... 9

- Style apex with second extension straight or irregularly curved, apex oriented distad (Figs 10g, 11h).................. 10

9 Aedeagal shaft broad in lateral view, ventral processes strongly divergent in ventral view.... I. rhynchosiae Einyu & Ahmed

- Aedeagal shaft slender in lateral view, ventral processes convergent in ventral view............. I. nebulosa Dworakowska

10 Style apex with second extension straight or slightly curved (Fig. 11h).......................................... 11

- Style apex with second extension irregularly and strongly curved (Fig. 10g)...................................... 13

11 Subgenital plate with long apical spine extended mesad (Fig. 11g).................... I. spinalis Cao & Dmitriev sp. nov.

- Subgenital plate without apical spine.................................................................... 12

12 Aedeagal shaft with pair of small projections apically, basal processes arising away from shaft on ventral side............................................................................................... I. nigra Dworakowska

- Aedeagal shaft with pair of thin processes apically, basal processes arising from dorsal side of shaft...... I. africana Ahmed

13 Basal processes of aedeagus bifid apically (Fig. 10i)............................... I. bifurca Cao & Dmitriev sp. nov.

- Basal processes of aedeagus tapered to single point apically................................................... 14

14 Pygofer dorsal appendage with dorsal extension distinctly longer than broad basal section; aedeagus with basal processes not surpassing shaft............................................................. I. microcephalica Dworakowska

- Pygofer dorsal appendage with dorsal extension shorter than broad basal section; aedeagus with basal processes surpassing shaft.............................................................................................. 15

15 Pygofer dorsal appendage with dorsal extension shorter than half length of broad basal section............................................................................................... I. sclerosa Dworakowska & Lauterer

- Pygofer dorsal appendage with dorsal extension longer than half length of broad basal section...... I. debilis Dworakowska