1908.] DR. KNUD ANDERSEN ON BATS. 227 



and fifth digits ; in ^ . fallax^ hirsutus, and jamaicensis (and 

 concolor ?) the first phalanx is proportionately shorter, its indices 

 being: third digit 281-298, fourth digit 245-260, fifth digit 186- 

 201 ; in all other species the phalanx is proportionately longer, 

 its indices being : third digit 327-357, fourth digit 279-304, fifth 

 digit 217-240. 



(F) Hairing on limbs and interfemoral. — In most species the 

 posterior pai't of the interfemoral and the upper side of the tibia 

 are very thinly haired or, at least on cursory inspection, almost 

 naked ; in a few species, especially ^. hirsutus^ toliecus, and aztecus, 

 they are densely furred. 



(G) Colour. — The specific variation in colour is extremely small, 

 the individual variation considei-able. As a means to separate the 

 species of this genus colour-characters must, therefore, be used 

 with great caution. — The general colour pattern is this : upper side 

 some shade of brown, under side lighter; very often four facial 

 stripes ; often narrow whitish mai'gins to the ears ; sometimes 

 white tips to the wings. Young (not full-grown) individuals darker 

 and duller than adults. — In most, if not all, species there is a darker 

 and a lighter colour extreme, as a rule (perhaps always) connected 

 by several intermediate stages ; the light-coloured extreme some- 

 times occurs in full-grown specimens with quite unworn teeth, 

 i. e. in specimens which have evidently just reached the matvire 

 age, but I have never seen it in decidedly immature (not full- 

 grown) individuals. A pair of white or whitish supraorbital and 

 infraorbital stripes are very often present, but they vary, some- 

 times even in the same species {A. jamaicensis, and others), through 

 all stages from complete absence to very strong development ; as a 

 rule (not always) they are sti-ongest in lighter-coloured indi- 

 viduals. White tips to the wings are most conspicuous in the 

 larger species {A. jylanii^ostris, hirsutus, jamaicensis), more in- 

 distinct or, as a rule, j)ractically wanting in the smaller species. 



(H) Size. — No less than ten species {A. glaucus, watsoni, 

 chiereus, rosenbergi, toltecus, quadrivittatus, phcmtis, aztecus, t^irpis, 

 nanus) are, externally, approximately of equal size, the forearm 

 varying betweeir 36"5 and 47 mm. Three species (A.planirostris, 

 hirsutus, jamaicensis) ai-e noticeably, or much, larger : forearm 

 53*5-76 mm. One (A. concolor) is intermediate: forearm about 

 50 mm. 



(I) Conclusions. — The principal, and in most cases the only 

 reliable, difl;erences between the species are cranial and dental. 

 No specimen of Artiheus ought to be identified without a careful 

 examination of the skull and teeth. 



Sjyecies. — In 1878, Dobson catalogued 5 forms of Artiheus, viz. 

 A. 2)lanirostris, A. 2y^(('nirostris var. concolor, A perspicillatus, 

 A. cineretts, A. quadrivittatus. The total number of forms 

 recognised in the present paper is 25 (14 species). The following 

 table gives, in chronological order, a view of all the forms 

 named, their type localities, their identification in Dobson's 

 Catalogue, and their identification in this paper :— 



