312 Mr. R. Shelford's Studies of the Blattidae. 



roacli and the anterior field of the wings of certain Acri- 

 diidae and Locustidae whicli lie lias proved to produce a 

 rattling noise during flight with the wings alone, neither 

 the legs nor the tcgniina taking any part in the operation 

 (Stett. Ent. Zeit. 1UU8, pp. 112^119). This rattling or 

 rustling noise is of course to be distinguished from the 

 true stridulation produced by insects at rest. The wing- 

 structure of Guna stridvlans { = caffroruvi, Stal) is by no 

 means exceptional, for not only have the other s})ecies of 

 the genus a similar wing-venation but other genera present 

 similar features; it would be interesting to learn from 

 observations in the field if any Blattidae produce a rattUng 

 noise when flying. 



Genus Gyna, Br. 



Gyiia, Brunner von Wattenwyl, Nouv. Sytit. Blatt., 



p. 26G (1865). 

 Trichomcra, Kirby, Ann. Mag. Nat. Hist., ser. (i, wiii 



p. 257 (1896). 

 Apctrogia, Kirby, op. cit., ser. 7, v, p. 281 (19UU). 



KEY TO THE SPECIES. 



1. rronotiuii with ;uiterii)r half casta- 



neous, posterior half oclireous . G. cajiifcimi, Gerst. 

 r. Pronotum not as above. 

 2. Pronotum with disc castaneuii.'*, 

 mar<,ans llavo-testaceous or 

 ochreous. 

 3. Tegiuiua flavo-marginate 

 throughout the greater i)art 

 of their length. 

 4. Eyes ((^) touching or nearly 

 touching on vertex of head. 

 5. Larger (19-20 mm. in 



total lengtli) .... (V. scutdli'jcfn, Walk. 

 5'. Smaller (15 nun. in total 



length) (r. costalis. Walk. 



4'. Eyes ((^ ) wide apart . . . (r. coste7ica, sp. n. 

 3'. Tegmina not ilavo-marginate 

 throughout the greater part 

 of their length. 

 4. Tegmina castaneous with 4 



ochreous n^aculae ...(?. glorioaa, Stal. 



