Two new species of Neoperla (Plecoptera, Perlidae) from China

Abstract Two species of the genus Neoperla from China are described as new: Neoperla furcostyla sp. n., and Neoperla similidella sp. n. The new species are compared to similar taxa.

In the present paper, we describe two additional species as new to science: Neoperla furcostyla sp. n., and N. similidella sp. n. from Guangxi autonomous region and Fujian Province, respectively. All types, including paratypes, are deposited in the Entomological Museum of China Agricultural University (CAU). Aedeagi were everted using the cold maceration technique of Zwick (1983). Description. Male. Forewing length 16.6-16.9 mm. General body color brownish. Distance between ocelli about as wide as diameter of ocellus. Head slightly wider than pronotum, lateral margins and M-line pale, a large medial portion brown with area between ocelli and a triangular patch on frons darker (Fig. 1A); compound eyes dark; antennae brown. Pronotum pale brown with medial portion brown (Fig.  1A); wing membrane subhyaline, veins brown; legs evenly brown. Abdomen brown, hemiterga darker.

Neoperla furcostyla
Terminalia. Tergum 7 process forming a sclerotized, upraised plateau, covered with many small sensilla basiconica (Figs 1B, 2A). Tergum 8 with a recurved quadrate process bearing small spines at distal margin. Tergum 9 without sensilla patches. Hemitergal processes of tergum 10 short and slightly curved (Figs 1B, 2A). Aedeagal tube very long and almost straight, but bearing a pale bifurcate structure with common stem located subapically (Figs 1C, 2B); dorsal surface heavily sclerotized and membraneous areas on ventral surface gradually enlarged toward tip of the tube. Aedeagal sac very short, about one fifth as long as tube, triangular in shape; with granules around sac apex and several dorsoapical spines and patch of smaller ventroapical spines (Fig. 2B).
Female. Unknown. Etymology. The specific epithet refers to the subapical fork of the aedeagal tube.

Distribution. China (Guangxi).
Diagnosis. The male of N. furcostyla is characterized by an elongate, almost straight aedeagal tube bearing a subapical fork with common stem. The aedeagal sac is triangular in shape and barely one fifth as long as tube; several dorsoapical spines and patch of  smaller ventroapical spines are present at apex (Figs 1C, 2B). The type of the aedeagus of the new species is also found in N. forcipata Yang & Yang, 1992 known from Mt. Wulingshan of Hunan Province of China, but the aedeagus of this species is different. In N. forcipata (Fig. 2C), the aedeagal tube is more robust and has an obtuse curve near the subapical fork, and the fork is much larger than that of N. furcostyla. The sac of N. forcipata though not everted, has an evident lateral flap subapically that is absent on the sac found in N. furcostyla. The new species is assigned to the Diehli subgroup of the Montivaga species group (Zwick 1983).
Notes. The holotype of N. forcipata Yang and Yang is apparently damaged at the base of the aedeagal tube, very possibly due to an overlooking of this elongate type of tube during the course of dissection. In this case, it is safe to cut the abdominal at the fifth or preceding segments in order to keep this kind of tube intact after dissection. Description. Male. Forewing length 12.6-12.8. General body color dark brown. Distance between ocelli ca. 1.5X as wide as diameter of ocellus. Head slightly wider than pronotum, with a large black ocellar patch barely touching the compound eyes and a black trapezoidal patch on frons (Fig. 3A); compound eyes dark; antennae dark brown. Pronotum dark brown with pale brown to brown lateral margins (Fig. 3A); wing membrane pale brown, veins dark; legs yellow, basal third of tibiae darker. Abdomen dark brown, terminalia darker. Cerci dark except 1 st segment brown.

Neoperla similidella
Terminalia. Process of tergum 7 large, rounded and upraised, mostly covered with sparse sensilla basiconica but margined with denser sensilla basiconica patches (Fig.  3B). Tergum 8 with an upcurved tongue-shaped process, fringed with small distal spines. Tergum 9 without sensilla patches. Hemitergal processes of tergum 10 slightly curved medially (Figs 3B, 4D). Aedeagal tube darkly sclerotized, slender and mostly straight but with a gradual dorsoapical curve, dorsal surface heavily sclerotized, with many spinules on dorsal surface (Fig. 3C). Aedeagal sac about half as long as tube and gradually curved ventrad; along dorsoapical surface with a patch of small and median sized spines, and two rows of large stout spines apically (ca. 7 spines) (Figs 3E, 4A); mostly ventral and lateral surfaces of apical half of sac with small spines (Figs 3D, 4C); apex of the sac with several medium sized spines (Figs 4B).
Female. Unknown. Etymology. The specific epithet refers to the great similarity to the species N. idella Stark and Sivec, 2008. Distribution. China (Fujian Province).
Diagnosis. This species is characterized by its dark body color and the head with a large black ocellar patch barely touching the compound eyes and a black trapezoidal patch on frons. The aedeagal sac has a patch of small and medium sized spines, and two rows of large stout spines that range from mid length to the apex of the dorsal surface (ca. 7); ventral and lateral surfaces of the apical half of the sac have small spines and the apex of the sac has several medium-sized spines. The aedeagus of the new species is very similar to that of N. idella, however in that species the aedeagal tube lacks a subtle dorsoapical curve and the sac is more strongly curved ventrad (Stark and Sivec 2008, Figs 36-37). In addition, the aedeagal sac of N. idella lacks a ventroapical patch of small spines and also lacks medium sized spines. Both species bear similar patches of large spines on the dorsoapical margin of the sac but in the new species the ventrolateral patch of small and medium spines is located nearer the sac apex than in N. idella.