1901.] ON BUTTERFLIES FROM THE AVIIITE TSTILE. 25 



4. On some Butterflies from the White Nile collected by 

 Capt. H. N. Dunn of the Egyptian Army. By Arthur 

 Ct. Butler, Ph.D., F.L.S., F.Z.S., &c. 



[Received November 14, 1900.] 



Alfcbougb the nurnber of species recorded in the present paper 

 is small, sevei-al of them are of considerable interest. 



In the genus Teracolus are three interesting species — T. phlegyas, 

 T. liagorcj and T. (jlycem. The first was originally described from 

 what I took to ' be the wet phase of the species, and whicli 

 consequently was for some time confounded with the insect to 

 which Miss E. M. Sharpe has given the name of T. difficilis; Capt. 

 Dunn has now secured both sexes of the true wet phase, which 

 shows that the nearest relation of T.phlKjyas is T. bacrjms (the 

 form hithei-to regarded as the wet phase being an intermediate 

 phase of the species). T. liagore is represented in the collection 

 by M'et and intermediate phases ; the intermediate phase having 

 both a large and small form, the large form will represent T. stt/gni 

 of Felder, and the small form T. odysseus of Swiuhoe. T. glycera, 

 v/hich I originally described from a single male example without 

 definite locality, has now come to hand in all its seasonal phases, 

 and proves to be an easily distinguishable form of the T. aniigone 

 group : the males always characterized by an unusually straight 

 outer margin to the primaries and hardly a trace of the dividing 

 spot at the posterior edge of the orange apical patch ; the female 

 of the wet phase is dimorphic, either with an orange apical patch 

 very distinctly divided by an angulated dusky line, or with the 

 apex dusky brown enclosing four to five hastate yellowish streaks. 

 Another species of interest, of which both sexes w^ere obtained, 

 is Belenois ahyssinka of Lucas (the wet phase approaching typical 

 B. gidica), of which the Museum previously only possessed three 

 examples ; this is the insect for which, thinking it nndescribed, 

 M. Oberthiir has proposed to use M. Boisduval's MS. name of 

 " Pieris alHca." It is apparently strictly limited to N. Africa, though 

 tlie (typical) dry-season phase more nearly resembles the dry pliase 

 of the widely distributed southern and eastern B. ivestwoodi than 

 might be expected from a comparison of the respective wet phases 

 of the two species. 



Perhaps one point of interest in this collection should be noted, 

 namely, the resemblance of the species generally to, and their 

 frequent identity with, those of Aden. At least fifteen of the 

 Butterflies occurring at Aden are conspecific with those in the 

 present collection, whilst Precis boopis and Ttracolas liagore are 

 nearly related to the Arabian forms ; perhaps, hoN^ever, the 

 strangest thing is that Lininas chrysij^pus is tetramorphic both at 

 Aden and on the AVhite Nile, and it is probable that the same is 

 true of Cafopsilia forella, three of the four forms of that species 

 being in the present collection. 



