CHRYSOMELIM. 



Genus AMBROSTOMA, MotschulsJcy. 



Ambrostoma, Motschulsky, Schrenck's Reisen Amurl. ii, 1860, p. 205 ; 

 Baly, Trans. Ent. Soc. l^ond. 1879, p. 192, pi. 2, f. 16; Weise, Arch. 

 Naturg. Ixiv, 1898, p. 196. 



Genotype, Ambrostoma quadri-impressum, Motsch. 



This genus includes three species, namely, quadri-impressum, 

 Motsch., fortunei, Baly, and mahesa, Hope. In general build they 

 resemble each other, although the two former are larger in size. 

 Another character common to the three species is the structure of 

 the metasternuin, which is bordered on each side only by a deep 

 furrow, the apex being without any furrow, and truncate. Baly 

 laid considerable emphasis on this character alone, and has 

 included the three species in one genus. But A. mahesa, Hope, 

 the only one known from within our faunistic limits, differs from 

 the other two in having the second segment of the antennse 

 shorter than the fourth, while in quadri-impressum and fortunei 

 the second segment is equal to the fourth. Baly did not, 

 apparently, take notice of this difference. 



The combination of metasternal and antennal characters might 

 be considered sufficient to justify the placing of A. mahesa in a 

 separate genus, but not having enough material, I do not propose 

 to do this at present. On the other hand A. mahesa cannot be 

 put back into the genus Chrj/solina, because of the form of its 

 metasternum ; since in Chrysolina the metasternum is bordered 

 by a channel all round, including the apex, and this character is 

 constant throughout the large genus. A. mahesa occurs in Nepal 

 and the other two species are found in China and Siberia. 



Range, discussed above. 



26. Ambrostoma mahesa, Hope. 



Chrysomela mahesa, Hope, in Gray, Zool. Misc. 1831, p. 30. 

 Ambrostoma nepalense, Motsch., Schrenck's Reisen Amurl. ii, 

 1860, p. 228. 



Colour metallic bluish-green, underside with a cupreous sheen. 

 Anterior, lateral and posterior margins of the pronotum and 

 three longitudinal bands, one median and two lateral, bright 

 metallic cupreous red ; margins of elytra all round, suture, and on 

 each elytron the following pattern : internal to the humerus a 

 short basal longitudinal band meeting a post-basal transverse band 

 from which proceed two longitudinal bands, usually anastomosing 

 (sometimes not) on the apical area, all bright metallic cupreous 

 red, which in darker specimens becomes a steel-blue. The 

 scutellum shares the colour of the suture. 



Head broad ; eyes situated on the extreme lateral parts, on the 

 inner side of them are the thickened roots of the antennae, the 

 inter-antennal space being very deeply depressed and impressed 

 with three lines meeting at a point in the middle, one running 

 along the middle to the vertex and the other two obliquely to the 



