490 Mr. G. J. Arrow on 



existence of which in other species of Parastasia he was not 

 then aware of. I have identified the female of this insect 

 in a specimen * which clearly connects this section of the 

 genus with the succeeding one. This female presents a 

 remarkable resemblance, not only in its short ovate form 

 and its simple claws, but also in sculpture and coloration, 

 to the typical form of that group, P. hiniaculata, Guer, Its 

 right determination is sufficiently evident, however, from 

 the sharp downward curved thoracic spine, the black 

 scutellum and the rounded black spot upon the pygidium, 

 in all of which it exactly agrees with the male Parastasia 

 Pascoci. The female has two squared spots on the posterior 

 part of the prothorax, as in Mmaculata, which in the male 

 unite together and with the black scutellum to form a 

 large heart-shaped mark. 



These differences both in bodily form and marking 

 occasion a dissimilarity between male and female which is 

 very remarkable ; but still more extraordinary is an un- 

 described species allied to this in which the two sexes 

 differ not only in form, marking and the structure of the 

 claws, but also in a striking degree in the form of the 

 mesosternum and the sculpture of the elytra. Indeed so 

 complete is the distinction that I long hesitated to 

 associate the two. Considering, however, that all the 

 differences here occurring in combination have already been 

 found in other representatives of the genus, except one, 

 viz. the presence of a long sternal process in the female 

 only, and as the degree of development of this structure 

 has been found to have no systematic importance, distin- 

 guishing species closely related, and varying within the 

 limits of a single species, there seems no valid reason for 

 resisting the evidence which points to the identity of the 

 two forms. Four specimens acquired by M. Oberthlir 

 from Van Lansberge's collection were taken in the same 

 locality and of these two of ditferent sexes were, judging 

 from the labels, taken simultaneously. Three specimens 

 without a sternal process show no variation and are all 

 males, while the fourth, with a process, is a female and 

 shows an evident relationship, in colour and marking, to 

 ihe male. I propose to call this insect Parastasia mirahilis. 



* Note. This specimen, collected by Wallace at Singapore, was 

 found in the Hope Collection at Oxford, but has been transferred to the 

 British Museum, and a co-type of the male form is noAv in the former 

 collection. 



