Embolemus walkeri Richards, 1951

Olmi, Massimo, Mita, Toshiharu & Guglielmino, Adalgisa, 2014, Revision of the Embolemidae of Japan (Hymenoptera: Chrysidoidea), with description of a new genus and two new species, Zootaxa 3793 (4), pp. 423-440 : 432-433

6. Embolemus walkeri Richards, 1951

( Fig. 4 )

Embolemus walkeri Richards 1951: 814 ; Yasumatsu 1954: 1; Belokobylskij 1990: 68; Olmi 1996: 114; van Achterberg & van Kats 2000: 254, 255.

Redescription. Female. Micropterous; length 3.1–4.9 mm. Head and mesosoma dark-testaceous or brown; antenna, legs and metasoma testaceous. Antenna geniculated, filiform, without rhinaria, shorter than head + mesosoma + metasoma (49:59); antennal segments in following proportions: 27:6:11:12:12:10:11:11:10:13; antennae articulated to strong frontal processes; antennal toruli very far from upper margin of clypeus. Head ( Fig. 4 A) dull, granulated, covered with fine and short hairs, with dorsal side almost flat; anterior region of dorsal side little tapering; occipital carina complete; ocelli absent; frontal line absent; eye ( Fig. 4 A) small, much shorter than head (5:30); region of face from clypeus to antennal toruli with two longitudinal and median sutures very convergent much nearer clypeus than antennal toruli. Maxillary palpi 4-segmented; labial palpi 2-segmented. Third segment of maxillary palpi broadened. Pronotum dull, granulated, covered with short hairs, crossed by strong anterior transverse impression, with two fine lateral incomplete carinae beginning at posterior border and reaching about 0.5 × length of pronotum (about 0.7 × in large specimen from Japan, Saimyoji); anterior collar very short; pronotal tubercle reaching tegula; disc long, with median longitudinal groove in holotype and in large specimen from Japan, Saimyoji, without groove in smaller specimens. Scutum small, subrectangular, granulated, with track of median groove. Notauli absent. Parapsidal lines present, hardly visible near lateral margins of scutum. Scutellum ( Fig. 4 B) subcircular, very small, dull, granulated. Metanotum ( Fig. 4 B) very short, transverse, not easily distinguishable. Mesopleuron and metapleuron granulated, with some irregular transverse keels. Meso-metapleural suture complete. Metapleuron fused with propodeum. Propodeum with spiracles normally prominent; anterior dorsal surface flat, granulated and weakly rugose, with two lateral pointed apophyses at border with posterior surface; posterior surface inclined, granulated and transversely striate; dorsal surface of propodeum with deep median depression situated at border between anterior and posterior surface ( Fig. 4 C); dorsal surface with two lateral carinae connecting spiracles to pronotal tubercles, by running laterally to metanotum, scutellum and scutum. Fore wing strongly reduced, slightly longer than tegula, reaching the depression at anterior border of propodeum. Hind wing absent. Petiole short. Tibial spurs 1/2/2.

Male. Unknown.

Material examined. Types: Holotype of E. walkeri Richards , ♀: P.R. CHINA: Zhejiang, near Ning Po (= Ningbo), Da-Laen-Saen, 1500–2500 ft., 5–16.XI.1892, with ants, J.J. Walker leg. (Cruis of the Penguin), Present by Lords of the Admiralty 1893-52 ( BMNH). Paratype of E. walkeri Richards : JAPAN: Honshu, Fukushima Prefecture, Aizu Province, Akai, Minato-Mura, 29.IV.1950, in nest of Myrmica sp., Y. Kurosawa leg., 1♀ ( ELKU) (misid. E. ruddii by Olmi 1996). Other material. JAPAN: Honshu, Tochigi Prefecture, Mashiko-cho, Saimyoji, 11.IX.2005, S. Maehara leg., 1♀ (TUA); Honshu, Aomori Prefecture, Misawa-shi, Misawa, Hotoke-numa, N 40.821 E 41.380, 25.V.2012, Shunpei Fujie leg., 1♀ (TUA); Kyushu, Miyazaki Prefecture, Miyakonojo-city, 11.IX.2008, in Cryptomeria forest, pit hole trap, Hiroshi Makihara leg., 1♀ (TUA); Shikoku, Kochi Prefecture, Tosa Province, Mt. Kuishi, 1100 m, 28.III.1954, K. Morimoto leg., 1♀ ( ELKU) ( Yasumatsu 1954) (misid. E. ruddii by Olmi 1996).

Hosts. Unknown.

Distribution. Palaearctic Region: Japan (Honshu, Kyushu, Shikoku); Oriental Region: P.R. China (Zhejiang).

Remarks. In the Eastern Palaearctic region, E. walkeri has been confused in the past with E. ruddii , because of the great similarity of the females of the two species (unluckily the males of E. walkeri are unknown). In fact, Olmi (1996) synonymized the two species. Afterwards, van Achterberg and van Kats (2000) revalued E. walkeri on the basis of some morphologic differences (shape of hind femur; presence/absence of fine lateral carina on pronotum; head more or less robust in lateral view; eyes more or less large and more or less close to antennal toruli; colour of head and metasoma; sculpture of head; pronotum with or without median groove; length/width ratio of antennal pedicellus). We have examined a very large series of females of E. ruddii and have compared them with the holotype and paratype of E. walkeri . In addition, we have studied further four females of supposed E. walkeri from Japan not available at time of Olmi (1996) and van Achterberg & van Kats (2000). Because of the large variability of E. ruddii , we cannot confirm the differences presented by van Achterberg & van Kats (2000). However, we have observed in all studied specimens of both species a good morphologic difference: propodeum with (in E. walkeri ; fig. 4C) or without (in E. ruddii ; fig. 5C) a median depression located at border between anterior flat surface and posterior inclined surface. This depression is not present not only in all examined females of E. ruddii , but also in the holotype of E. krombeini ( Fig. 3 C). We believe that this is a true good difference justifying the separation between E. walkeri and E. ruddii (in addition to E. krombeini ).

Figures

FIGURE 3. Embolemus krombeini, female holotype. A. Head in lateral view. B. Mesosoma in dorsal view. C. Outline of border between anterior and posterior surface of propodeum. Scale bar 1.1 mm for A, 0.6 mm for B, 0.3 mm for C.

FIGURE 4. Embolemus walkeri, female holotype. A. Head in lateral view. B. Mesosoma in dorsal view. C. Outline of border between anterior and posterior surface of propodeum. Scale bar 1.9 mm for A, 0.9 mm for B, 0.7 mm for C.