of Upupa and Irrisor. 241 



long-billed birds the interior of both mandibles is provided with 

 a hollow space for the reception and action of a lengthened 

 tongue, or for the temporary retention of their food. This very- 

 remarkable and peculiar structure has been noticed by no author 

 (as far I am aware) except Wagler, who in his definitions of 

 Upupa and Epimachus, in which last genus he includes Irrisor, 

 notices this character, but without making any comment on its 

 singularity. It is sufficiently evident from this structure that 

 both Upupa and Irrisor have very little affinity to the Tenuiros- 

 tres, in which the tongue is remarkably lengthened and adapted 

 to the purposes of suction, and Irrisor cannot therefore be referred 

 to the Nectariniida, as supposed by the Baron de la Fresnaye. 

 The fact is, that the beaks of these birds are not constructed for 

 suction but for probing, i. e. for reaching into deep holes and cre- 

 vices in quest of the larvse of insects. We know that the hoopoe 

 obtains its food by inserting its beak into the holes made in the 

 ground by coprophagous insects, and it is probable that the Irri- 

 sor feeds in a similar manner upon the larvae which perforate 

 decayed trees. 



The beaks of these two genera of birds present another cha- 

 racter unnoticed by all previous authors, and, like the former one, 

 believed to be peculiar to these two genera alone. The basal and 

 medial portion of the ridge of both mandibles is obtusely and 

 roundedly carinate, but in proceeding towards the apex, the ridge 

 first becomes flattened, then hollowed, and at last deeply grooved. 

 In the Irrisor this flattened portion commences in both mandi- 

 bles about the middle of the beak, and soon changes into a flat- 

 bottomed groove, which towards the apex is divided into two by 

 a fine intermediate ridge. In Upupa the flat space commences 

 about two-thirds of the total length from the base, and wants the 

 intermediate ridge. With these slight difierences the beaks of 

 the two birds may be considered as quite identical in structure. 

 Basal portion. Apical portion. 



UPUPA 



IRRISOll- 



A -n 



while they difi^er as before remarked from those of all other known 

 birds. These characters are shown in the above figures, which 

 represent magnified transverse sections of the mandibles. 



