Thrips alni Uzel

(Figs. 62–68)

Female macroptera. Body including legs uniformly yellow; antennal segments I to II yellow, III shaded often with basal half pale, IV to V brown often with basal half slightly pale, VI to VII brown; fore wings including clavus uniformly weakly shaded in greyish brown; prominent body setae dark brown, S1 setae pale, S2 setae pale or distinctly paler than lateral setae (S3–S5) on abdominal tergites. Head (Fig. 62) rounded at cheeks. Ocellar setae III outside ocellar triangle, posterolateral to fore ocellus. Postocular setae I and III longer than longitudinal diameter of hind ocelli, II and IV minute. Antennae (Fig. 63) 7-segmented, III to IV without apical neck, IV to V pedicelate. Pronotum (Fig. 62) with 21–31 discal setae; posteroangular setae 2 pairs; posteromarginal setae 3 pairs, setae I the longest. Mesonotum with CPS anteromedially. Metascutum (Fig. 64) with wide spaced longitudinal striae medially except anteromedially, lines of sculpture sometime converged to middle at posterior margin; median pair of setae far from anterior margin; CPS present. Fore wing first vein with seven basal and three distal setae. Abdominal tergites III to VI with no lines of sculpture extending to mesad of S1 setae; tergite II with 4 lateral marginal setae; III to V with S2 setae pale same as remaining tergal setae; tergite VIII (Fig. 65) with posteromarginal comb complete, S2 setae almost as long as S1 setae; tergite IX with two pairs of CPS; sternite I with two microsetae anteromedially; sternite VII with S1 setae much far from posterior margin; pleurotergites without discal setae and ciliate microtrichia.

Male macroptera. Body pale yellow. Antennal segment VI with more 20 setae. Abdominal tergite VIII (Fig. 66) with posteromarginal comb medially; tergite IX with S1 setae anterior to level of S2 setae, slightly longer than S2 setae, their bases equidistant; sternites III to V or VI each with a small circular pore plate (Figs. 67, 68).

Specimens examined. JAPAN, Hokkaido: Tomakomai City, Takaoka-shinrinkouen Park, 8 females, 9 males on Alnus hirsta [Betulaceae], 24-ix-2004, T. Tsutsumi (FU). Honshu: Gunma Pref., Kusatsu-cho, 2 females on leaves of Alnus hirsta, 13-v-2002, M. Masumoto (TUA). Yamanashi Pref., Sutama-cho, Kanayama-daira: 8 females on leaves of Alnus hirsta, 8-vii-1994, S. Okajima (TUA); 26 females, 8 males, on leaves of Alnus hirsta, 1- vii-1995, S. Okajima (TUA). Yamanashi Pref., Sutama-cho, Tokusa-toge (alt about 1400 m): 4 females, 1 male on leaves of Betula sp., 3-ix-2002, M. Masumoto (TUA); 6 females on leaves of Alnus hirsta, 3-ix-2002, M. Masumoto (TUA); 6 females on leaves of Alnus hirsta, 14-vii-2006, M. Masumoto (TUA); 4 females on leaves of Betula sp. [Betulaceae], 14-vii-2006, M. Masumoto (TUA); 1 male on leaves of Polygonum japonica [Polygonaceae], 14-vii-2006, M. Masumoto (TUA); 1 male on leaves of Betula sp., 14-vii-2006, M. Masumoto (TUA); 3 females on flowers, 14-vii-2006, M. Masumoto (TUA); 1 female on flowers of Lespedeza sp. [Fabaceae], 22-viii-2006, M. Masumoto (TUA). Yamanashi Pref., Fujiyoshida City, Fuji-rindou, nr. Mt. Fuji: 4 females on leaves of Alnus hirsta, 24-vii-2001, M. Masumoto (TUA); 6 females on leaves of Alnus hirsta, 18-ix-2001, M. Masumoto (TUA); 9 females on leaves of Alnus hirsta, 30-v-2003, M. Masumoto (TUA). Nagano Pref., Norikurakougen, 5 female on flowers of Thalictrum sp. [Ranunculaceae], 21-viii-2006, M. Masumoto (TUA).

Distribution. Japan (Hokkaido, Honshu), Europe.

Biology. This species is common on Betulaceae in mountainous areas and northern part of Japan.

Comments. This species is here newly recorded from Japan, although Tsutsumi (1997) reported it as Thrips sp. 9. It is very similar to T. palmi and discrimination of these species is often difficult in females but the males can be distinguished easily: in T. alni, abdominal pore plates are very small and present on sternites III to V or VI, whereas in T. palmi these are regularly wide on each segment, although the habitats of the two species may not overlap.