222 FAUNA HAWAIIENSIS 



extremely minute sculpture ; there are no true striae, but angular ridges separated by 

 broad grooves ; in some species the alternate ridges are more elevated, but in others 

 there is little difference in this respect : the lateral margin is always yellow. The under- 

 surface is piceous variegate with yellow. 



We have received about fifty specimens of this species ; in all of them the thoracic 

 setae are absent, except that in one specimen the seta exists on one side, and is of 

 normal size'. A variety occurs in which the colour is more extensively yellow, and 

 then there is an extreme resemblance to Metroinenus linibattis, but in that species the 

 sides of the elytra are always more broadly yellow than they are in these extreme 

 varieties of A. transicns. 



Hab. Kauai (Perkins). Makaweli, 2500 ft., in February 1896, and again in 

 February 1897. Nos. 668 and 703. 



Mesothriscus, gen. nov. 

 Corpus apterum. Prothorax utrinque seta unica ad medium lateris sita munitus. 



(i) Mesothriscus vagans, sp. nov. 



Piceo-niger, antennarum basi, palpis pedibusque testaceis, antennis extrorsum 

 obscurioribus ; prothorace subtransverso, basin versus fortiter angustato, angulis pos- 

 terioribus obtusis ; elytris sat profunde striatis, interstitiis haud deplanatis, margine 

 laterali rufa. Long. 7 — 9 mm. 



The species varies a good deal in colour, the thorax being sometimes blackish and 

 a little paler at the sides, while in other cases it is red, and intermediate conditions 

 occur. The thorax is much rounded at the sides in front, and a good deal narrowed 

 behind ; the base is not straight, but a little directed forwards on each side ; the hind 

 angles are both obtuse and indefinite. The legs are usually dirty yellow. Eighty or 

 ninety specimens. The thorax varies a good deal in form. 



Hab. Molokai Mountains, 4000 — 4500 ft., on several occasions in June and 

 August 1893 (Perkins). — ? Maui (Perkins). 



I have some little doubt as to the correctness of the labellingr of the single individual 

 on which the Maui record is based. It is numbered 384, which refers to Haleakala 

 III. 1894. I incline to think it is a specimen from Molokai that has been misplaced 

 during the preparation. 



' In a letter recently received from Mr Perkins he suggests that the absence of the setae in A. transiens 

 may be to a considerable extent a post mortem occurrence. It is quite probable that this may be the case. 

 In other words A. transiens may be a species liable to lose its thoracic setae from slight mechanical causes 

 more easily than most other species do. If shewn to be the case, this would in itself be of considerable 

 interest. 



