3.10 Nemophora divina species group

Nemophora divina group (Kozlov 1997e: 138)

Diagnosis. This species group can be characterized by the following features: the forewing base has a W-shaped light mark extending over 1/3 of the forewing length, or interrupted and formed into a small arcuate spot at the base and a line in the middle; the distal 1/3 of the forewing has pale light stripes that follow the direction of veins; the apical 1/3 of aedeagus is formed by the left wall only which forms a broad lobe; and the anellus with a pair of articulated carinae at the base of juxta.

Remarks. In addition to the above diagnosis, Kozlov (1997e) also characterized this species group by the basal 1/2 of female antennae with dense scale cover based on the adults of N. assamensis . However, we do not regard it as one of the diagnoses of this species group because this character is rather common in the family Adelidae, especially Nemophora .

Here, we place N. trimetrella Stringer, 1930 in the divina group because this species shares the above morphological diagnoses, especially in the male genitalia. Although the basal marking of the forewing does not form into W-shaped but a basal spot and a middle line, we consider this type to be an early evolutionary stage of the forewing pattern. In addition, we identified a new species belonging to this species group in Taiwan, China in this paper. Thus, the divina group consists of five species: N. divina (Caradja, 1939), N. assamensis Kozlov, 1997, N. magnifica Kozlov, 1997, N. trimetrella Stringer, 1930, and N. songgangensis sp. nov. Therefore, all members of this species group are found in China.

Key to species of the divina group based on external morphology

1 Forewing base with a large W-shaped marking.............................................................. 2

- Forewing base with an arcuate basal spot and a middle line.......................................... N. trimetrella

2 Forewing central fascia complete......................................................................... 3

- Forewing central fascia interrupted in the middle forming two spots............................................. 4

3 Forewing central fascia relatively broad and nearly equal in width; apex of forewing with 8 to 10 obvious and stout radial striae......................................................................................... N. divina

- Forewing central fascia slender and narrow in the middle; apex of forewing with 8 indistinct and slender radial striae...................................................................................... N. songgangensis sp. nov.

4 Proximal line of W-shaped basal mark of forewing broad, expanding along costal margin; distal line medially broken................................................................................................ N. assamensis

- Proximal line of W-shaped basal mark of forewing narrow, not expanding along costal margin; distal line unbroken.................................................................................................. N. magnifica

Key to species of the divina group based on male genitalia

1 Apex of medial valvar lobe at 1/2 valvar length....................................................... N. divina

- Apex of medial valvar lobe at 4/5 valvar length............................................................. 2

2 Valva longer than uncus, with smooth inner margin; suspensorium far beyond posterior margin of vinculum.... N. magnifica

- Valva shorter than uncus, with serrate inner margin; suspensorium not far beyond posterior margin of vinculum.......... 3

3 Anterior part of vinculum distinctly wide and rounded; lateral valvar margins (viewed ventrally) posteriorly form an distinct acute angle with lateral margins of vinculum...................................................... N. assamensis

- Anterior part of vinculum distinctly wide and rounded; lateral valvar margins (viewed ventrally) posteriorly almost parallel to lateral margins of vinculum..............................................................................4

4 Uncus with week median keel; base of median process with two distinct anterior angles laterally; arrow-head of juxta short........................................................................................... N. trimetrella

- Uncus with distinct median keel; base of median process without anterior angles laterally; arrow-head of juxta slender and pointed......................................................................... N. songgangensis sp. nov.