S12 Mr. R. Shelford's Studies of the BlaMidae. 



roach and the anterior lield of the wings of certain Acri- 

 diidae and Locustidae which he has proved to produce a 

 rattling noise during flight with the wings alone, neither 

 the legs nor the tegmiua taking any part in the operation 

 (Stett. Ent. Zeit. 1908, pp. 112-119). This ratthng or 

 rustling noise is of course to be distinguished from the 

 true stridulatiou produced by insects at rest. The wing- 

 structure of Gyna strididans { = caffrorum, Stul) is by no 

 means exceptional, i'or not only have the other species 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 rattling 

 noise when Hying. 



Genus Gyna, Br. 



Gipia, Brunner von Wattenwyl, Nouv. Syst. Blatt., 



p. 266 (1865). 

 Trichomcra, Kirby, Ann. Mag. Nat. Hist., ser. 6, xviii 



p. 257 (1896). 

 Apctrvgia, Kirby, up. cit., ser. 7, v, p. 281 (1900). 



KEY TO THE SPECIES. 



1. Pronotum with anterior half casta- 



neous, posterior half ochreous . G. aqjiicina, Gerst. 

 r. Pronotum not as above. 

 2. Pronotum with disc castaneous, 

 margins fiavo-testaceous or 

 ochreous. 

 3. Tegmina fiavo-jnarginate 

 throughout the greater part 

 of their length. 

 4. Eyes ( ,^ ) touching or nearly 

 touching on vertex of head. 

 5. Larger (19-20 mm. in 



total length) .... G. scutdli'jcra, Walk. 

 5'. Smaller (15 mm. in total 



length) G. costalis. Walk. 



4'. Eyes ( ^ ) wide apart . . . G. castanea, sp. n. 

 3'. Tegmina not flavo-marginate 

 throughout the greater part 

 of their length. 

 4. Tegmina castaneous with 4 



ochreous maculae . . . G. gloriosa, Stal. 



