346 MR. M. JACOBY ON NEW [JunC 5, 



the disk is often close, at other times remote and very irregular. 

 IMost of tlie specimens in tlie present collection were obtained at 

 Hakodate and are with few exceptions females, which may be recog- 

 nized at once by the very curious appendage of the last abdominal 

 segment, unique amongst the numerous species of this genus with 

 which I am acquainted ; this structure consists in a triangular 

 acutely pointed kind of sheath, hollowed at its base and placed upon 

 the middle of the last abdominal segment ; the pygidium ends in a 

 blunt protuberance and seems capable of closing the posterior opening 

 of the sheath ; I find no reference to any similar structure in this 

 or any other species. The males are much smaller, and the penis is a 

 slender curved tube, narrowed and blunt at its apex. The colour of 

 the thorax and elytra varies from jjurplish to blue or green, and the 

 latter have two or three more or less distinct longitudinal smooth 

 spaces ; wings are absent. 



'O' 



Chrysomela virgata, Motsch. 



Obtained in numerous specimens at Gensau in Corea. 



Chrysomela obscurofasciata, Jac. 



This species, described by myself in the Proc. Zool. Soc. 1885, 

 seems to be only a variety of the preceding species, with which 

 it entirely agrees in size, shape, and sculpture ; the entire insect is, 

 however, dark puiplish-blue in colour with an elytral still darker 

 band, the latter in C virgata is reddish cupreous. 



Melasoma octodecimpunctata, n, sp. 



Metallic greenish, the six basal joints of the antennse, the sides of 

 the thorax, and the legs fulvous ; elytra very closely punctured, 

 fulvous or testaceous, each elytron with nine rounded black spots 

 (1, 3, 2, 2, 1). 



Length 2-3| lines. 



Head finely and closely punctured, greenish aeneous ; antennae 

 scarcely extending to the base of the thorax, black, the basal six 

 joints fulvous. Thorax three times broader than long, the sides 

 broadly flattened, fulvous, the disk metallic green, very finely punc- 

 tured, bounded at the sides by a deep longitudinal groove, which is 

 impressed with deep punctures ; scutellum metallic green. Elytra 

 very closely punctured, with traces of longitudinal strife, fulvous or 

 flavous ; the suture, a spot at the shoulder, three, placed triangularly 

 at the base, two slightly larger ones placed transversely at the middle, 

 two below the latter, and another transversely shaped spot near the 

 apex, blackish ; legs entirely fulvous. Underside metallic greenish. 



At first sight this species seems identical with the well-known M. 

 20-punctata, but the insect is quite distinct from the last-named ; 

 the sides of the thorax in 31. IS-punctala are much more broadly 

 I'ulvous, and the green colour does not encroach on it except by a 

 small S|)ot at each side (as iu M. '20-punctata) : but the principal 

 difference is to be found in the number, shape, and position of the 

 elytral spots ; these latter are not elongate but rounded ; the six 



