108 Longicornia Malayana. 



Cacia mstabilis. 



Saperda Vanikorensls, Boisd. Voy. Astrol. ii. 515, Col. pi. ix. 



fig. 18 (1835). 

 Corethrophora semiluctiiosa, Blanch, Voy. Pole Sud, iv. 301, 



pi. xvii. fig. 15 (1853). 

 Cac'ia anthriboides, Pasc. Journ. Entom. i. 130, pi. v. fig. 5 (1860). 

 Cacia Idstriordca, Pasc. Journ. Entom. i. Q^iQ (1862). 



C. nigra, pube subtilissima grisescente vel alba tecta; pro- 

 thorace generaliter albo-nigro-vittato ; elytiis convexis, sub- 

 tiliter punctatis, basi regularibus. 



Hah. — Batchian, Bourn, Morty, Ceram, Waigiou, Aru, Dorey. 



Black, with a very fine greyish or whitish pubescence ; the 

 front between the antennee more or less concave ; the prothorax 

 generally with a central white stripe between two black ones ; 

 elytra convex, very finely punctured, the base regular j other 

 characters variable. 



Length 6 — 8 lines. 



From a large number of specimens now before me I have not 

 the slightest doubt that all the names given above are referrible 

 to one and the same species. Under ordinary circumstances I 

 should have taken the earliest name, but putting aside the ob- 

 jection that this is simply a barbarism, and that at the very mo- 

 ment of giving it the author believed that though ticketed (^itidiqiiee) 

 from Vanikoro the insect nevertheless came from New Guinea 

 or the Celebes, and its adoption, therefore, would be only to per- 

 petuate an error, the obvious convenience of a collective desig- 

 nation for a species subject to such an extraordinary amount of 

 variation becomes almost a necessity. 



'J'he names of these four forms may be maintained as so many 

 centres from which to survey the species. Starting from the com-, 

 monest forms, which seem to group themselves round C. histrionica, 

 we find that they are black, with a white band across the elytra pos- 

 teriorly, the apex, scutellum, and elytra around it, also white. A 

 stripe from the scutellum passing along the suture joins the band, 

 and then we have the Corethrophora semiluctiwsa. Through several 

 varieties the white increases, the black between the band and stripes 

 gradually diminishing and disappearing, in which state it is the C.an- 

 tliriboides. Sometimes there is a black spot on the white near the 

 shoulder, and the sutural stripe is prolonged to the apex ; this gives 

 two black patches to each elytron. In one beautiful specimen the 



