Spilogona subfuscisquama ( Ringdahl, 1932 )

Spilogona subfuscisquama ( Ringdahl, 1932) View in CoL

Fig. 6 C View FIGURE 6

Limnophora (Spilogona) subfuscisquama Ringdahl, 1932: 156 View in CoL . Type-locality: “ 2♂ in der subarktischen Region bei Abisko von mir gefangen, Juli 1918 ” [ SWEDEN, Torne Lappmark ].

Notes. Huckett (1965) synonymized Spilogona subfuscisquama View in CoL with Spilogona pusilla View in CoL . However, the holotype of Spilogona pusilla View in CoL agrees well with Spilogona albisquama View in CoL but not with Spilogona subfuscisquama View in CoL (see above). The male terminalia of Spilogona subfuscisquama View in CoL is very different from the figures of Spilogona albisquama View in CoL given by Ringdahl (1956) and by Hennig (1959a), and from the figures of the male terminalia of Spilogona pusilla View in CoL given by Huckett (1965).

Among specimens of Spilogona pusilla in the CNC I found specimens of Spilogona subfuscisquama from Salmita Mines (N.W.T). In this collection, some specimens of Spilogona subfuscisquama from Fort Churchill (Manitoba) were also found among Spilogona aenea Huckett, 1965 . All these specimens had hind femur without any pv setae and the male terminalia as in Hennig’s figures of Spilogona subfuscisquama ( Hennig, 1959b: Taf. XVIII, fig. 354). The colour of the calypters of these specimens is variable from light yellow to brownish.

Spilogona subfuscisquama ( Ringdahl, 1932) View in CoL is thus a valid species with an arctic-subarctic distribution, which is different from the similar Spilogona pusilla View in CoL with a wider subarctic-subalpine distribution. The colour of the calypters is variable in both species and cannot be used for the identification of these species.

Material examined. CANADA, NWT: 4♂♂, Salmita Mines, 64°05’N 111°15’W, N.W. T GoogleMaps ., 4.vii.1953, leg. J.G. Chillcott ( CNC) . CANADA, Manitoba: 3♂♂, Fort Churchill , 23.vi.1952, leg. C.D. Bird ( CNC) .

The very similar Spilogona subfuscisquama and Spilogona pusilla are closely allied to species such as Spilogona humeralis , Spilogona atrisquamula , Spilogona malaisei Ringdahl, 1920 and Spilogona wrangeli Hennig, 1959 by their small size (3–4 mm), subovate abdomen, brown or blackish thorax without stripes, anepisternum without interspatial setae, scutellum with downwardly-directed preapical setulae on upper border of declivities, and mid tibia without v setae.

Males of these species can be separated by the following couplets:

1 Both calypters dark brown................................................................... S. atrisquamula View in CoL

- Calypters yellow, or lower calypter light brownish........................................................... 2

2 Scutum seen from in front with anterior border of presutural region more or less greyish; sternite V with a blunt rounded caudal margin ( Fig. 6A View FIGURE 6 )............................................................................. S. humeralis View in CoL

- Scutum concolorous on presutural region, deep brown; sternite V with a pointed caudal margin ( Figs 6B, C View FIGURE 6 )............. 3

3 Abdomen dark grey with indistinct and ill-defined black marks; facial edge a little projecting beyond level of profrons, or not ................................................................................................... 4

- Abdomen pale or whitish-grey, with distinct and well-defined black marks; facial edge not projecting beyond level of profrons............................................................................................. 5

4 Hind femur without pv setae; costa without spinules, with short setae; surstylus curved and shorter than cerci ( Fig. 6D View FIGURE 6 )................................................................................................ S. malaisei View in CoL

- Hind femur with weak elongated pv setae in basal half; costa with spinules; surstylus not curved and as long as cerci ( Fig. 6E View FIGURE 6 )........................................................................................... S. wrangeli View in CoL

5 Hind femur with weak, but distinct elongated pv setae in basal half; sternite V with a deep trapezoidal median notch ( Fig. 6B View FIGURE 6 ); prementum completely shining................................................................... S. pusilla View in CoL

- Hind femur without pv setae; sternite V with a deep triangular median notch ( Fig. 6C View FIGURE 6 ); prementum often with light dust in middle................................................................................ S. subfuscisquama View in CoL

Females of all these species are very similar and difficult to distinguish. More specimens from different localities need to be studied to identify possible differences. Spilogona malaisei View in CoL and Spilogona wrangeli View in CoL are the most distinct from the others, as in the following couplets:

1 Abdomen seen from behind entirely black and mostly glossy, without dorsal marks................................. 2

- Abdomen grey and with paired brownish marks on dorsum.......................................................3

2 Costa without spinules, with short setae........................................................... S. malaisei View in CoL

- Costa with spinules........................................................................... S. wrangeli View in CoL

3 Facial edge not projecting; scutum pale grey, with or without clear brown marks; scutellum wholly pale grey............................................................................. S. pusilla View in CoL &? S. atrisquamula View in CoL &? S. subfuscisquama View in CoL

- Facial edge a little projecting; scutum and scutellum with deep brownish dust, at least at basal angles of scutellum................................................................................................... S. humeralis View in CoL

Spilogona pusilla View in CoL is distributed not only on the plains but also in mountainous areas, where specimens are characterized by a darker colour not only on the lower calypter but also on the scutum, as in Spilogona humeralis View in CoL . The latter species can be separated from Spilogona pusilla View in CoL by the slightly projecting facial edge. Females of Spilogona subfuscisquama View in CoL , like males, probably have the prementum with light dust in the middle, and can be separated from the other species by this character.

Distribution. PALAEARCTIC: Sweden. NEARCTIC: NWT, Manitoba.