COLEOPTERA 203 



(7) Disciiochus afcrrinms. sp. no v. 



Niger, antennis palpis tarsisque rufis ; thorace transverso, basin versus leniter 

 angustato, angulis posterioribus indistinctis ; elytris suboblongis, profunde striatis, striis 

 externis punctatis, internis plerumque impunctatis. Long. 10, lat. 3 mm. 



Plate VI. fig. 6. 



Thorax rather large, gently rounded at the sides, without posterior angles, the 

 lateral margin but little more strongly elevated behind ; impunctate, basal impressions 

 indistinct. Elytra rather narrow, elongate and parallel-sided, deeply and regularly 

 striate ; the external striae, at least, are distinctly punctured, and sometimes all the 

 striae are. The legs are long, pitchy black, the tarsi red. 



This species varies a good deal as regards the depth ol the elytral striae and their 

 punctuation. So far as I can judge, the variation is partly connected with locality. The 

 more deeply sculptured forms approximate a little to D. crythropns. Additional remarks 

 on the variation are given below. 



This species is extremely subject to the attacks of Laboulbeniaceae, some of the 

 individuals bearing many specimens of these parasitic plants. Specimens taken from 

 D. atc?-}-iiiiiis were numbered i 2 1 8 by Prof. Roland Thaxter. 



Hab. Kauai (Perkins) : Halemanu in May, Koholuamano in April, Makaweli in 

 January and February ; the high plateau in August. The species was also met with 

 in October. 



We have a series of 91 examples of this species, and I have submitted them to a slight 

 examination as to their variation. The method adopted was to divide them first roughly 

 into three groups, viz. ( i ) a form I have called typical, the characters of which are that 

 the form is rather slender, the black colour very deep, and the inner striae ot the elytra 

 not perceptibly punctured : (2) specimens I have called variant, as they depart more or 

 less distinctly from (i) in the direction of (3) : (3) van a, specimens of large size, broad 

 form, with the thorax rather broader and more narrow behind, the legs not so black, 

 and the striae of the elytra comparatively strongly punctured. All the specimens were 

 then compared with the three selected exponents and each specimen treated as belonging 

 to one of the three groups in accordance with which one of the types it most resembled. 

 The extremes of (i) and (3) look so different that 1 thought they might possibly be 

 two species, but I am quite convinced that this is not the case. I give below the 

 numbers found in each locality so far as our labelling and records of locality permit 

 this to be determined. Koholuamano, iv. 95, without any number, i typ., 2 variant ; 

 Halemanu, v. 95, i without number, var. a ; Koholuamano, iv. 95, No. 505, 2 variant : 

 Koholuamano, 16. iv. 95, No. 508, i var. a ; Halemanu, 4000 ft., v. 95, No. 514, i var. a ; 

 Koholuamano, 15. iv. 95, No. 516, S typ., i var. a; Koholuamano, 13. iv. 95, No. 517, 

 typ. 4, variant 9; Koholuamano, iv. 95, No. 519, i variant; Koholuamano, iv. 95, 

 No. 519, I variant; Koholuamano, iv. 95, No. 527, i variant; Koholuamano, 13. iv. 



