236 DR- KNUD ANDERSEN ON BATS. [Apr. 7, 



(region of third phalanx of third digit) more or less whitish. A 

 pair of whitish or greyish-white supraorbital stripes, as a rule 

 indistinct, sometimes altogether wanting. — This is the usual colour 

 in young, not full-grown individuals; it never occurs in the 

 mature A . planirostris. 



At a somewhat later stage, the colour of the hinder back is less 

 smoky, more approaching dark brown in tinge, with the hair- 

 bases almost drab. The rest of the upper side, from the shoulders 

 forward, much of the same general colour, but the dark hair-tips 

 shorter, the hair-bases considerably lighter, varying from wood- 

 brown to greyish white ; very often the hair-tips in this region 

 of the upper side are so short as to more oi' less (or almost 

 completely) expose the light ground-colour, in which case thei-e, 

 consequently, is a contrast between the anterior and posterior part 

 of the upper side. The under side essentially as in immature indi- 

 viduals, though as a rule a shade lighter. Supraorbital stripes 

 often completely wanting, often rather indistinct, rarely strongly 

 developed; there is sometimes, though rarely, an indication of 

 infraorbital stripes. — This is the commonest colour in the adult 

 A. planirostris, very often occurring also in specimens with much 

 worn teeth. 



A considerably lighter colour is acquired by some adult indi- 

 viduals :— Upper side approaching Front's brown, base of hairs 

 almost ecru-drab. Anterior portion of upper side, from shoulders 

 forward, as a rule noticeably lighter, owing to the dark hair-tips 

 being shorter and the wood -brown hair-bases showing through. 

 Under side almost drab, with short greyish-white tips to the 

 hairs. Supraorbital stripes as a rule well marked, often strongly 

 developed, wood-brown or whitish ; there is often a more or less 

 definite indication of infraorbital stripes.— This stage evidently 

 represents the " light phase " so common in many bats : I never 

 saw a young A. j)lanirostris in this colour-stage; it is apparently 

 confined to the fully adult age, and it is only acquired by a limited 

 number of individuals. 



Thus there are three stages of colour : a dark and dull smoky 

 brown, a dark brown, and a Front's brown ; the two former come 

 very near to each other, the third, when fully developed, is 

 diftferent at a glance. The first is confined to the immature age ; 

 the second is characteristic of a majority of adults ; the third 

 seems to occur only in some fully adult and aged individuals ; it 

 is especially common in the largest race, A . p. fallax, but not rare 

 m. A. 2^. planirostris and trinitatis. 



Range. From Central Brazil (Bahia, Matto Grosso) and 



S. Bolivia (Caiza) to S. Mexico (Chiapas, Guerrero), including the 

 Yenezuelan coast islands (Trinidad, Tobago) and the southern 

 Windward Islands (Grenada), but excluding the rest of the West 



Indies. 



Remarks. — By the combination of the five characters given in 

 the brief diagnosis above, p. 234, A. planirostris (all races) is 

 readily distinguishable from all other species of the genus. The 



