( •■'■J ) 



$. rostvagiual platx' trianguhir, scaled latei-ally, seiiavated from tlie vagiual 

 jilatc by a Darrow strip of membrane ; vaginal opening longitndiual, the side-edges 

 of the opening raised to ridges, which terminate abruptly distally, while they 

 become gradnally lower proximally (I'l. XXll. f. (3). 



JIab. Aethiopian Kegiou.— Two subspecies. 



a. P. moi-gaiii moryani. 



*Murrii.iilii inonjaiii Walker, I.e. 



tJ?. Underside of abdomen white. 

 Hab. West and East Africa. 



In the Triug Miisenm 8 66,2 S ? from : Sierra Leone ; Ujiper Congo ; Cubal 

 River, Angola, March 1899 (Penrice) ; Dar-es-Salaam. 



b. P. mon/a/ii praedicta snbsp. nov. 



cJ ? . Breast and abdomen beneath with an obvions pinkish tint. Ui)perside 

 of body and forewing, and underside of wings also somewhat pinkish. Black 

 apical line of forewing, extending from costal to distal margin, broader than in the 

 preceding, black discal streak R''— M' also heavier. 



Hab. Madagascar. 



Type ((?) in coll. Charles Oberthiir ; & female specimen in coll. Mabille. 



Wallace, in Natural Selection, p. 146 (1891), speaking of the adjustment 

 between the length of the nectary of orchids and that of the proboscis of insects, 

 says : " In the case of xingraeciim sesquipedale it is necessary that the proboscis 

 should be forced into a particular part of the flower, and this would only be done 

 by a large moth burying its proboscis to the very base, and straining to drain the 

 nectar from the bottom of the long tube, in which it occupies a depth of one or 

 two inches only. ... I have carefully measured the proboscis of a specimen of 

 Macros/la ditentius from South America, in the collection of the British Museum, 

 and find it to be nine inches and a quarter long ! One from tropical Africa 

 {Macro«ila morgani) is seven inches and a half A species having a proboscis two 

 or three inches longer could reach the nectar in the largest flowers of Angraecam 

 sesijuipcdale, whose nectaries vary in length from ten to fourteen inches. That 

 such a moth exists in Madagascar may be safely i)redicted, and naturalists who 

 visit that island should search for it with as much confidence as astronomers 

 searched for the jilanet Neptune, — and I venture to predict they will be eipially 

 successful." 



As the tongue of P. morgani pracdirta is long enough — about 225 mm. = 

 8 inches — to reach the honey in short and medium-sized nectaries of Angraceum., 

 the moths will not abandon the flowers with esi>ecially long nectary without trying 

 to reach the fluid, which fills up, in hot-house specimens of Angraecum, about 

 one-fourth of the nectary. The result would be that flowers with excei)tionally 

 long nectaries would be as well fertilised as such with short nectaries by a moth 

 which could reach the fluid in the long nectaries only when a greater quantity 

 of nectar had collected. .V. morgani praedicta can do for Angraecum what is 

 necessary ; we do not believe that there exists in Madagascar a moth with a 

 longer tongue than is found in this .Sphingid. 



