COLEOPTERA 647 



The saddle along the middle of the thorax is rather wide, it is more elevated in 

 front in the male than it is in the female, and it bears in each sex 2 or 3 feeble trans- 

 verse ridges ; the slight longitudinal depression that runs along each side of it bears 

 a scanty pallid setosity, so feeble that it may be overlooked except in well-cleaned 

 specimens ; owing to the darker ground-colour of the female, these faint stripes are 

 more distinct in it. The elytra are densely and finely punctured and have no trace of 

 a glabrous area ; the variegation of the elytra is irregular and so variable that it cannot 

 be easily described. The legs are very slender in the female, and the clavate portion 

 in it is always infuscate so as to contrast strongly with the pallid basal part ; the tibiae, 

 though yellow are always darker at the tip, in the female more extensively than in the 

 male. The hind tarsi are slender and long. In each of the sexes there is a very 

 definite spot of white pubescence at the posterior extremity of the metasternal episterna. 



Dr Perkins reared a series of about 100 specimens of this species from wood tound 

 on North Kona, but of what tree I do not know. 



Hab. Hawaii, North Kona; the specimens emerged in Nov. and Dec. 1900. D. S. 



Plagitliniysus solitarius Sharp. 



P. soliiarius, huj. op. 11., p. 106. 



$ Nigricans, antennis, tibiis tarsisque rufis, femorum basibus testaceis ; elytris 

 nigro-rufis, maculis albidis ornatis ; thorace parum discrete albido-vittato ; tibiis pos- 

 terioribus dense nigro-hirsutis, tarsis albido-hirtis. Long, i i — 16 mm. 



This species has hitherto been known from a single male individual. The female 

 has now been discovered and proves to be very different in colour from the male. 

 Twenty-one specimens recently found are about eight of them females, the remainder 

 males. Two pairs were found in copula, so that there is no doubt as to the correct 

 association of the two forms as the sexes of one species. Some of the very small 

 specimens have the male coloration, but are certainly females. 



In the females found in copula the concolorous ferruginous ground-colour of the 

 male is replaced by black, while the elytra are midway between black and ferruginous. 



The species varies very much in size, the length being from 8 — 14 millimetres. 



The female of P. solitarms is very like the male of P. aequa/is, but it has the hind 

 tibiae densely hirsute, and the marks do not coalesce to form on the posterior part of 

 the elytra a white stripe. 



The difference in colour of the sexes found in copula is very remarkable, and so 

 is the variation in colour of the female. It is, however, quite possible that a larger 

 series mieht show that the male is also variable in colour in a similar manner. 



Hab. Oahu, Koolau range both to the north-west and south-east, and at various 

 dates from April to September 1901 (Perkins). D. S. 



S3-2 



