422 THE MARQUIS OFTWEEDDALE ON BATRACHOSTOMUS. [May 15, 



the vicinity of Darjeeling, Tung-goo and Karen-nee in Burma, Ma- 

 lacca, Sumatra, Borneo, Java, and Mindanao. 



It was an a priori and a natural inference of many ornithologists 

 that the bright-plumaged birds of the genus Batrachostomus must 

 be males, and the grey dull-coloured birds either females or imma- 

 ture examples, or else that they belonged to totally distinct species ; 

 for the Batrachostotni exhibit two very distinct phases of plumage — 

 the bright rufous or rufous bay (when adult), and the speckled, 

 spotted, and striated grey and brown and rufous brown dress. So 

 very diiferent an aspect do individuals falling under either one or 

 other of these two phases assume, that it was long before some 

 authors suspected that they in fact belonged to the same species, 

 though to the opposite sexes. This conclusion cannot even now 

 be considered as placed beyond doubt (for the Frogmouths may 

 be dimorphic) ; and it is therefore proposed to state and examine 

 the evidence on which it rests. Bonaparte (Consp. i. p. 57. no. 2) 

 seems to have been the first writer who announced that in the case 

 of B.javensis the sexes differed ; for he remarks (/. c.) : — -"Mas et 

 fem. inter se colore differunt uti Scops asio differt a Sc. naevia 

 auctorum." But his simile leads to the inference that he thought 

 the rufous birds were males and the grey females. A few years later 

 Prof. Schlegel (J. f Orn. 1856, p. 460) propounded the general and 

 more definite axiom that in all the Indian species of the genus 

 Podargus {Batrachostomus) the males are grey, the females rust- 

 coloured. At that time the Leyden Museum possessed examples of 

 two Asiatic species, identified by the Professor as B. parvulus {ex 

 Borneo and Malacca) and B. cornutus {ex Java, Sumatra, and 

 Borneo) ; and to these species must Professor Schlegel's dictum be 

 restricted, doubtless founded on numerous examples with the sexes 

 determined by the Dutch collectors. Oi B. parvulus { = B. affinis, 

 Blyth), ex Malacca and Borneo or Sumatra, I have not met with an 

 example, in either grey or rufous plumage, of which the sexes had 

 been determined by a competent collector. Yet, if B. affinis, Blyth, 

 is but a slightly smaller form of B. castaneus, Hume (of which there 

 is little doubt), and consequently the rufous phase of Otothrix 

 hodgsoni, then there is some confirmatory evidence of Prof. Schlegel's 

 opinion that the grey birds belong to the male sex. Examples of 

 B. cornutus, ex Sumatra and Botueo, in both plumages, with the 

 sexes determined, fortunately exist in England, and bear out the 

 Professor's conclusions. In the British Museum is preserved an 

 example, ex Sumatra, in grey plumage, and marked as being of a 

 male by its collector, Mr. "Wallace. Count Salvadori {I. c.) describes 

 a freckled rufous individual from Sarawak ; and the sex, as ascer- 

 tained by the collector, is stated to be female. Two pairs of this 

 species, collected in Banjarmassing by Motley, were examined by Mr. 

 Sclater; and he observed (P. Z. S. 1863, p". 212) that " the sexes 

 are very different in colouring, the male being minutely freckled with 

 brown and black, and the female bright rufous. liorsfield's figure 

 represents the female." As regards the remaining Asiatic species 

 there is also some evidence on this point. A bright rufous example 



