( :i2 ) 



?. rostAiigiiKil |iliil(' I riiui;;iil;ir, sfiilcil l:i,l('r;iliy, scpiiratcil IVtiiu t lie vaginal 

 jtlatc liy a narrow striji ol' lueinbiaiie ; vaginal ojuMiing lougitiulinal, the side-edges 

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

 become gradually lower jiroximally (I'l. XX 11. f. 0). 



Ilah. Aethiopian Region. — Two subspecies. 



a. I', mnrgani moryani. 



*.Uacriisilii iiiiinjani Walkor, I.e. 



c??. Underside of abdomen wliili'. 

 Hah. West and East Africa. 



In the Tring Museum 8 c?c?, L' ? ? from : Sierra Luone ; Uj)per Congo ; Cubal 

 River, Angola, March lS!»y (Penrice) ; l)ar-es-Salaatu. 



b. P. morfiditi praedicta subsp. nov. 



c??. Breast and abdomen beneath with an obvious pinkish tint. Upperside 

 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 

 l)receding, black discal streak R'' — M' also heavier. 

 llab. Madagascar. 



Type (c?) 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 Angraectim 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 occui^ies a depth of one or 

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

 Macrosila cluetitius 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 

 {Macros/la tnorffani) 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 Angraecum 

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

 such a moth exists in Madagascar may be safely predicted, and naturalists who 

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

 searched for the planet Neptune, — and I venture to predict they will be e(jually 

 successful." 



As the tongue of 1'. morgaiti praedicta is long enough — about 225 mm. = 

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

 the moths will not abandon the flowers with especially 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 exceptionally 

 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. X. 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. 



