Genera and Species of Bluttidje. 175 



Genus Platysilpha, nov. 



Allied to Derocalynimay Burm.. but much broader, pro- 

 uotuin about twice broader than long. ^ with tegmina 

 reduced, quadrate, extending to the middle of the second 

 abdominal tergite, marginal rield very broad. Wings rudi- 

 mentary. Meso- and metanotum only half the breadth of tiie 

 pronotum, and first abdominal segment narrower than second; 

 subgenital lamina transverse ; styles absent. ? very like 

 ? of Derocali/nvna, but bi'oader and oval. 



Type. Perisphmria niurina, Walk. 



The male of this species, when the tegmina are removed, 

 presents the remarkable outline shown in the figure, suggesting 

 that the flattened broad insect has developed from a narrow 

 form such as Derocalymma porcellio, Gerst., the mesonotum, 

 metanotum, and first abdominal segment retaining the primi- 

 tive narrowness. The marginal fields of the tegmina have 

 broadened relatively much more than the discoidal field, and 

 it is these which fill the gap between the posterior margin of 

 the pronotum and second abdominal tergite ; the tegmina are 

 capable of only the most restricted movement outwards, and 

 in the living insects are doubtless never moved at all. 



In the female, owing to the absence of tegmina, the thoracic 

 and abdominal segments are all equally broad ; it is the 

 broadening of the tegmina in the male which appears to have 

 prevented the broadening of the segments that they cover. 



PlaUjsilpha murina, Walk. (PI. X. fig. 20.) 

 Perlsphceria murina, Walker, Cat. Blatt. Brit. Mus. p. 178 (1868). 



S . Fuscous, with fine scale-like pubescence above. Head 

 and antennae piceous ; eyes approximated. Pronotum poste- 

 riorly truncate ; posterior angles acute, disk cucullate, marfins 

 lamellar, anteriorly slightly carinate. Scutellum prominent. 

 Tegmina castaneous, rugose, posteriorly emarginate, radial 

 vein beneath prominent, keeled. Wings shorter than 

 tegmina, infuscated. Eight abdominal tergites visible, first 

 to sixth divided by a transverse suture into a broad anterior 

 portion and a narrow posterior portion ; posterior angles of 

 all the tergites produced. Sujira-anal lamina quadrate. 

 Cerci very short. Abdomen beneath piceous, nitid ; sternites 

 failing to reach lateral margins owing to overlapping of the 

 tergites ; subgenital lamina transverse. Legs piceous. 



? . Similar to c? , but with a rust-red pubescence above; 

 mesonotum, metanotum, and first abdominal segment not 

 coarctate. 



