Sexual Di7norphisin in the Fiutelid genus Parastasia. 491 



Parastasia mirahilis, sp, n. 



Rufo-flava, capite, maculis prothoracis et scutelli corporeque subtus 

 nigris ; capite bituberculato, rugoso ; prothorace leviter, scutello vix, 

 punctatis ; elytris striato-punctatis. ^J cylindricus ; corpore subtus et 

 scutello toto nigris ; prothoracis basi macula nigra tridentata ornato ; 

 elytris rufis, regulariter striato-punctatis ; pygidio lateribus leviter 

 striolato ; naesosterno parum producto ; tarsorum 4 posticorum un- 

 guibus externis divisis. 5 l^-t^j depressa, pallidiora ; corpore subtus 

 plus minusve, prothoracis et scutelli maculisque minoribus nigris ; 

 singulo elytro disco profunde trisulcato, prope scutellum rugoso et 

 ad lateris medium subtiliter transverse sti-iato ; mesosterno valde 

 producto ; unguibus omnibus simplicibus. Long. 18 m.m. 



Rah. Malacca, 



The male exactly resembles that of P. Pascoei in its rather 

 peculiar coloration, but is more elongate, the sternal 

 process is almost absent and the thoracic mark is produced 

 forwards in the middle. The female is broader and less 

 convex, with a sternal process like that of Paseoci, and the 

 sculpture of the elytra is highly remarkable. The punc- 

 turation is almost obliterated but there is a finely striated 

 area in the middle of each side, the angles adjoining the 

 scutellum are rugose, and in the middle of each elytron 

 are three deep longitudinal furrows placed close together 

 and about one-third the length of the elytra. 



The next group, represented by the common P. himacu- 

 lata, has all the claws quite simple, in the male as well as 

 the female, and the mesosternum is not j^roduced. In the 

 typical species the sexes show no conspicuous difference, but 

 a closely related species by which it is represented in New 

 Caledonia and the New Hebrides has very distinct sexual 

 forms. This is P. Percheroni of Montrouzier (Plate XVII, 

 figs. 9 and 10), who correctly associated the two forms but, 

 being ignorant of sexual differences, regarded them as due 

 only to the age of the specimens. He has therefore im- 

 consciously described accurately the two sexes of the 

 species, that which he regarded as the extreme pale 

 variety being the male. Besides the colour differences 

 described by him, this has a somewhat longer antennal 

 club aiid the prothorax is very different in shape, being 

 smaller, less convex, and sharply angulated at the sides. 

 The female varies greatly in coloration, but according to 

 the considerable number of specimens I have examined in 



