1S89.] MR. W. F. KIRBY ON NEW ODONATA. 297 



the black of the wings has heroine first blue-black, then brightly 

 shot with bluish purple, and finally streaked at the base with metalHc 

 blue and green. Then, again, if the white of the secondaries was 

 first modified into yellow and orange as in Bracca and Prcesos (in 

 which the primaries are still black and white), one can see how the 

 bands on the primaries o( Milionia drucei and M. snelleni, if derived 

 from such a source, may have remained orange after those of the 

 secondaries had become vivid crimson. 



It has been said that colour is of no value as a guide in classifi- 

 cation, but I am not at all sure that, if the natural order of its 

 development were strictly looked to, it would not be of assistance in 

 guiding one to a judicious arrangement of allied genera. 



EXPLA]!fATION OF PLATE XXXI. 



Fig. 1 . Bracca bajtdaria, p. 294. 



2. Craspcdosis e.rfcniiafa, p. 29.5. 



3. Lifhopsvcke mifiqiia, from tlie typical specimen, p. 294. 



4. Fore wing of Prtesofs marianti, p. 2ti4. 



5. Ca/ospi/a lettcnmela, p. 29.5. 



6. Restoration of Lithopsyche. p. 294. 



3. Descriptions of new Genera and Species of Odouata in 

 the Collection of the Britisli Museum, chiefly from 

 Africa. By W. F. Kirby, F.E.S., Assistant in the 

 Zoological Department, British Museum, Natural 

 History, S. Kensington. 



[Received April 26, 1889.] 



On looking through the collection of Odonata in the British Mu- 

 seum lately, I found examples of some very interesting s[)ecies which 

 appear to be undescribed, and which form the subject of the present 

 [laper. Among these, the most important is Tatocnemis malgasska, 

 a species representing in Madagascar two remarkable Eastern generii, 

 Priocnocnemis and Idiocnemis, hitherto only known from the Philip- 

 pines and New Guinea respectively. 



The following is a list of the genera and species which I projiose to 

 describe : — 



Odonata. 



LIBELLULIDJE. 



LlBELLULIN*. 



Orfhetrum. cmnarensc, n. s Cameroons. 



MfhrkiTnanta reziu, n. s Mad agascar. 



^SHNIDiE. 



G-OMPIIINiE. 



Pseudogomphus {n. g.) insignis, n. s Cameroons. 



Anax fiMatus, n. s CLili. 



