552 Appendix to Rev. K. St. Aubyn Roger.s' Bionomic 



persistency, exactness, and comjDleteness with wbich they 

 reproduce the pattern and colouring of their models, the 

 very variable and abundant PiancwK — the species of 

 which, though few in number in comparison with the 

 allied ^cr«?/p, are very difficult to distinguish satisfactorily. 

 Every variation in both sexes appears to be faithfully 

 copied throughout tropical and sub-tropical Africa wherever 

 the genus Phmema prevails. Aurivillius (Rhop. ^thiop., 

 pp. 530-1) has recorded eight instances in which this 

 mimicry is palpable, and the case here noted is an addition 

 to that list. The mimicry mentioned by Mr, S. A. Neave 

 (Novit. Zool, xi, p. 333, 1904) of the British East African 

 form of Planeina icllus, Auriv., by Pseudacrcva terra, Neave, 

 — captured on the same day at Entebbe — is another 

 recorded instance ; and, looking to the rather dull and 

 unattractive aspect of these buttertlies, and to the evident 

 comparative rarity of the PsendacneiB, it may reasonably 

 be conjectured that they have not been very assiduously 

 observed or collected, and that the extension of field 

 research will bring to light more mimicries between 

 members of these two genera. 



It is a pleasure to name the species here described 

 after the author of the very interesting memoir to which 

 this is an appendix, not only in recognition of his valuable 

 services to African entomology, but in view of his having 

 himself (^ee above, pp. 508 and 523) pointed out the 

 mimetic relation existing between this Psciulacrxa and 

 Plaitcma montanf. Mr. St. Aubyn Rogers has recorded 

 that the $ of the Pscudacnva was sent to liim from Shimba 

 ("IC miles W. of; about 1,200 ft."), while the $ was 

 captured by himself at " Rabai, 14 m. N.W. of Mombasa, 

 on July 28, 1906." 



Pscvdacrma trimenii, Butler.* 



The intimate alliance of this form of I^scudacrxa with the 

 West African P. hoisduvalii, Doubl., was recognised by me 

 in 1869 (Trans. Linn. Soc. Lond., xxvi, p. 517), and after- 

 Avards better explained with the aid of fuller material in 

 1887 and 18«9 (S. Afr. Butt., I, p. 298, and III, p. 405). 

 I showed how closely in both sexes tiiineaii, the South- 

 Eastern form, copied Acriea acara, Hewits., of the same 

 region, just as hoisduvalii mimicked the West African 



* Ent. M. Mag., xi, p. 57 (1874). 



