2G6 Mr. G, J. Arrow on Sexual Dimorphism in 



the tiiorar, the scutcllum and the elytra, Avith the cxcep-- 

 tion of a pale longitudinal vitta upon each bordering the 

 suture and usually extending to half the breadth, of a deep 

 green. The suture is narrowly green. The thorax is nar- 

 rower than in the female and is rather more sharply angu- 

 lated in the middle of the sides. 



The following is a closely related species. 



Adordosoma metallicnm, sp. n. 



Cylindricum, rufotestaceum, nitidissimum, pedum intermediormn 

 et posticorum tarsis tibiarumqiie extremitatibus nigris ; capite ru- 

 goso, vertice nitido vix punctato ; protliorace distincte marginato vix 

 punctatOj'lateribus angulatis, angulis anticis acutis, posticis rectis j 

 elytris grosse lineato-punctatis. 



^ . Capitis vertice, prothoracis medio elytrisque viridibus vel viri- 

 dicocruleis. Long. 13 mm. 



$. Major, capite prothoraceque rubris, elytris viridibus vel viridi- 

 cceruleis. Long. 15 mm. 



Hah. North China, Shanghai. 



This is a larger species than A. tenuelimhatum and has 

 not the deeply striated elytra of that and the two original 

 species of the genus, approaching in this respect and in 

 colour A. chromaticu'/n. The male is similarly coloured to 

 that of A. teymielivibatum, but the dark colour extends over 

 the whole of the elytra, and the patch on the thorax reaches 

 the front and hind margins. In the female the elytra are 

 also wholly green or blue, but the head and thorax are a 

 metallic red. The thoracic mark is sometimes represented 

 by a pair of faint dark marks in the middle of the base of 

 the thorax. 



In the neighbouring genus Popillia sexual dimorphism 

 appears again. Fabricius described an insect belonging to 

 this genus of which the upper surface is black under 

 the name of Ceionia rujijocs, and two other forms, red 

 and green respectively, were described by Newman, 

 who, however, suggested the possibility of all three 

 being varieties of a single species. Attention to the 

 form of the abdomen and legs shows at once that the 

 metallic green insects {Popillia seneas of Newman) are 

 females and the black individuals males, those with the 

 elytra more or less red being also males and probably only 

 immature. Burmeister associated the three forms, but 

 announced that the black and green colours were most 



