A study of the genus Protosticta Selys, 1855, with descriptions of four new species from Vietnam (Odonata: Platystictidae) Phan, Quoc Toan Kompier, Tom Zootaxa 2016 4098 3 529 544 9WYZ9 [180,421,151,177] Insecta Platystictidae Protosticta Animalia Odonata 9 538 Arthropoda species socculus sp. nov.  ( Figure 7A–K)    Typespecimens.  Holotype: male, Aso, Dong Giang district, Quang Nam Province, central Vietnam, 28.V.2015, Quoc Toan Phan leg.;  Paratypes: 4 males, same date, location and collector as the holotype; 4 males, Bhalee, Tay Giang district, Quang Nam Province, 19.IX.2015, Quoc Toan Phan leg.   Etymology. The specific name  socculusis derived from the Latin word “ socculus” (meaning slipper), in reference to the slipper-shaped structure at the tip of the paraprocts.   Description of male holotype. Head( Fig. 7A). Anteclypeus and labrum pale blue with inferior margin of labrum black. Antennae black, basal half of second segment pale yellow; postclypeus, genae, frons, vertex and occiput entirely black. Prothorax( Fig. 7B) almost entirely pale yellow, with anterior and posterior lobes black dorsally. Synthoraxdull black with pale yellow stripe over metepisternum, black line over interpleural suture and mostly pale yellow metepimeron. Legspale yellow with black stripe over flexor surface; spines black. Wings( Fig.  7I) hyaline, 13–15 postnodal veins in both wings. Pterostigma brown. Abdomenlong and thin, black with pale yellow markings as follows: S1–2 short, ventral half pale yellow; S3–7 very long, blackish brown with whitish anterior ring and indistinct brown sup-apical ring; S8–9 shorter, dorsum of S8 blackish brown, large part of basal segment bluish white; S9 bluish white with anterior and posterior margin black; S10 entirely black. Anal appendages( Figs. 7C–G) black; cerci strongly curved downward; paraprocts with elongated tip, tapering, with a prominent slipper-shaped cup-like structure bearing a long spine on its distal margin. Penile organas in Fig. 7H.  Measurements. Hindwing 19; abdomen including appendages 44.  Female. Unknown.  Variation in paratypemales. In the paratypemales, the slipper-shaped cup-like structure at the tip of the paraprocts is not as prominent as in the holotype( Figs. 7J–K), but the spine at the distal margin can be seen easily in lateral view.  Measurements of paratypemales. Hindwing 19–20; abdomen including appendages 43–44.  Differential diagnosis. P. s o c cu l usspec. nov. appears to be closely related to  P. khaosoidaoensisjudging by the elongated shape of the paraprocts, which both have a very large cup-like structure with a spine at the distal margin on their apex on the dorsal side. It can be separated from that species as follows: (1) In  P. socculus spec. nov., cerci with only one protuberance ventrally at midpoint ( Figs. 7C, 7E), two protuberances in  P. khaosoidaoensis( Fig. 10B). (2) In  P. socculus spec. nov., the tip of the cerci is structurally complex ( Fig. 7F), flattened and rounded in  P. khaosoidaoensis( Fig. 10C). (3) In  P. socculus spec. nov., the dorsum of the synthorax is completely black ( Fig. 7A), a pale yellow line along the dorsal carina in  P. khaosoidaoensis( Fig. 10A).