Chaetocnema tristis Allard, 1889 Was originally described from “ Saïgon ” (renamed Ho Chi Minh City in 1975) in Vietnam ( Allard 1889 ). Ruan et al. (2019) recently redescribed and illustrated C. tristis ; hoWever, no host plant information has been published thus far. Its knoWn geographical distribution includes China , Vietnam , and Thailand ( Ruan et al. 2019 ). Recently, adults of this species Were collected by the second author (PKD) on bamboo in Meghalaya, northeastern India . This is the first report of C. tristis from India , representing a Western extension of its knoWn distribution by about 500 km, and first indication of its host plant. Chaetocnema tristis is the largest among 47 Indian congeners and the second largest Oriental species of the genus (3.5–4.0 mm long) behind only Chaetocnema wallacei Baly, 1877 (3.5–4.5 mm long) (see Ruan et al. 2019 ). The specimens collected in India match Well With the original description of Allard (1889) and the redescription and images provided by Ruan et al. (2019) . Chaetocnema tristis is characterized by the general color of the specimens varying greatly from shiny black ( Fig. 1 ) to yelloW-broWn or red-broWn ( Fig. 2 ), While the vertex is invariably and uniquely colored red-yelloW or red-broWn ( Fig. 3 ), the excavation on the metatibia very deep ( Figs. 1, 2 ), the flask-shaped spermatheca ( Fig. 4 ), and the aedeagus in ventral vieW With apical denticle small and acute ( Fig. 5 ). HoWever, the length of the specimens collected in India ranges from 2.77–3.85 mm as against 3.5–4.0 mm given by Ruan et al. (2019) . The specimens are deposited in the Indian Council of Agricultural Research - National Bureau of Agricultural Insect Resources (NBAIR), Bengaluru (accession no. NIM/NBAIR/ CIL/CHRY/230222) and the Travancore Insect Collection, Kerala Agricultural University (KAU), Vellayani.

Mathew, Sandra Maria & Prathapan, K. D., 2022, Chaetocnema tristis Allard, 1889 (Coleoptera: Chrysomelidae: Galerucinae: Alticini) New to India, The Coleopterists Bulletin 76 (2), pp. 296-297 : 296

Chaetocnema tristis Allard, 1889 Was originally described from “ Saïgon ” (renamed Ho Chi Minh City in 1975) in Vietnam ( Allard 1889). Ruan et al. (2019) recently redescribed and illustrated C. tristis; hoWever, no host plant information has been published thus far. Its knoWn geographical distribution includes China, Vietnam, and Thailand ( Ruan et al. 2019). Recently, adults of this species Were collected by the second author (PKD) on bamboo in Meghalaya, northeastern India. This is the first report of C. tristis from India, representing a Western extension of its knoWn distribution by about 500 km, and first indication of its host plant. Chaetocnema tristis is the largest among 47 Indian congeners and the second largest Oriental species of the genus (3.5–4.0 mm long) behind only Chaetocnema wallacei Baly, 1877 (3.5–4.5 mm long) (see Ruan et al. 2019). The specimens collected in India match Well With the original description of Allard (1889) and the redescription and images provided by Ruan et al. (2019). Chaetocnema tristis is characterized by the general color of the specimens varying greatly from shiny black ( Fig. 1) to yelloW-broWn or red-broWn ( Fig. 2), While the vertex is invariably and uniquely colored red-yelloW or red-broWn ( Fig. 3), the excavation on the metatibia very deep ( Figs. 1, 2), the flask-shaped spermatheca ( Fig. 4), and the aedeagus in ventral vieW With apical denticle small and acute ( Fig. 5). HoWever, the length of the specimens collected in India ranges from 2.77–3.85 mm as against 3.5–4.0 mm given by Ruan et al. (2019). The specimens are deposited in the Indian Council of Agricultural Research - National Bureau of Agricultural Insect Resources (NBAIR), Bengaluru (accession no. NIM/NBAIR/ CIL/CHRY/230222) and the Travancore Insect Collection, Kerala Agricultural University (KAU), Vellayani.

Host Plant. Collected on unidentified bamboo ( Poaceae : Bambusoideae ) by sWeeping.

Material Examined. 2♂, 10♀, India: Meghalaya / Barapani / N25°41′17.6′′, E91°55′5.1′′ 993m / 6.vi. 2013 / Prathapan KD Coll. /Ex Bamboo; 1♂, 4♀, same data except for a date of 7.vi.2013 and Without “Ex Bamboo”; 3♀, India: Meghalaya /Bhoirymbong / 14.xi.2013 / N25°43′23.0′′, E92°2′22.9′′ /alt. 895m / Prathapan. K.D. Coll. (19 KAU, 1 NBAIR). New country record for India.

Figures

Figs. 1–5. Chaetocnema tristis. 1) Black form, dorsal habitus (scale = 1.0 mm); 2) Red-broWn form, lateral habitus (scale = 0.5 mm); 3) Head, frontal vieW (scale = 0.50 mm); 4) Spermatheca (scale = 0.25 mm); 5) Aedeagus, ventral vieW (scale = 0.5 mm).