Sexual Dimorphism in the Bvielid genus Parastasia. 489 



colour which does not vary in a considerable number which 

 I have examined. 



Parastasia alternata, sp. n. 

 Crassa, fulvo-rufa, capite, scutello, fasciaque transversa humeral i 

 partem anteriorem tertium vix obtegente, pedibus corporeque subtiis 

 plerumque nigris, margine tenuissimo protlioracis elytrorum pygi- 

 diique fuscescente ; capite grosse, prothorace subtilitex-, punctatis, 

 scutello fere impuuotato, elytris leviter sulcatis et punctatis, pectore 

 fulvo-hirto, processu mesosternali brevissimo, abdomine striolato ; 

 (^ tarsorum mediorum et posticorum unguibus divisis, pygidio nitido 

 vix punctato ; ^ unguibus omnibus simplicibus, pygidio grosse 

 punctato. Long. 20 m.ni. 



Hob. N. India : Allahabad (Bowring). 



The black P. vitiensis, Nonf., as already discovered by 

 Dr. Ohaus, is the female of P. dolens, Fairm., which, with 

 P. melanocc2)hala, Burm., he has regarded as constituting a 

 separate section on account of the elongate club of the 

 antenna. The male of P. dolens, however, is very variable 

 and has a tendency to assume the female coloration. It 

 is normally red, somewhat darker on the elytra, and with 

 three longitudinal black stripes on the prothorax. Two 

 specimens in M. Oberthlir's collection, however, have the 

 elytra black and a third has entirely assumed the black 

 colour of the other sex. P. vielajiocephala, Burm., hardly 

 differs sexually in colour, but it and P. dolens both show the 

 same difference in the claws as the insects just described. 



Another group consists of insects in which the sexes 

 show the same difference in claw-structure, as well as a 

 colour ditference, but in these there is a long acute meso- 

 sternal process. These constitute the vittata group of Dr. 

 Ohaus, who has announced the black P. atra to be the 

 female of P. vittata, in which the prothorax has a red 

 border and median line, which I have no doubt is correct. 

 The length and form of the sternal process vary very 

 considerably in this species. 



P. hclleri, Ohaus, of which the female is as yet unknown, 

 is a very nearly related insect. 



To this group also belongs Echmatophorus Pascoei, 

 Waterh. (Plate XVII, figs. 1 and 2), the original specimens 

 of which being of one sex only were placed in a new 

 genus by Mr. Waterhouse, owing to the distinctive 

 form of the male, produced by the short and broad pro- 

 thorax, and the presence of the long sternal process, the 



