South African Butterjiies. 383 



but Mr. Spruce (Jomni. Linn. Soc. Zool. ix. 357) gives 

 an instance in which females also were undoubtedly 

 present. It is interesting to find the same phenomenon 

 presented by C. Florella in Basuto-land^ Mr. Bowker 

 describing it as follows^ viz : " Dur-ing my trip to No- 

 Man's-Land, in March, 1869, I crossed the Maluti Moun- 

 tains at two different points, going and returning, and 

 throughout the journey, whenever there was a gleam of 

 sunshine between the prevalent showers, the exodus of 

 Florella and Rhadia continued in one uninterrupted 

 stream. These butterflies were to be seen in countless 

 numbers, from the deepest and darkest valleys through 

 which the Orange River forced its way, up to the highest 

 peaks, 10,000 feet above the sea; and all ivere steadily 

 ■moving on Eastivard. Sometimes one of them would stop 

 to take a sip from a tempting Gladiolus, or even turn 

 back a few yards for that purpose, but it would be only 

 for a minute, and then off he would huiTy again, as if 

 fearful of being left behind by his comrades. I have 

 noticed the same swarms in the Traus-Keian Country, 

 and also in the Cape Colony ; in the latter, I believe, 

 other members of the Pieridce were concerned." It has 

 never been my own good fortune to witness one of these 

 wonderful moving hosts, and I can therefore express no 

 opinion on the subject ; but it may be worth while to 

 note, in connection with it, the well-known habit of almost 

 all Pierinoi of proceeding straight onward, with more or 

 less directness and rapidity in their flight. Even the 

 weak and fragile Tenas-species pursue this course, though 

 their flight is slow and near the ground ; and with Pieris, 

 Callosune, &c., it seems to be the rule. I lately was 

 much struck with this in the case of such robust species 

 as Pieris Cliarina, P. Severina, and P. Gidica, which 

 were very numerous near Grahamstown, and might be 

 seen to a considerable height above the ground, on fine 

 mornings, winging their way in one direction. Though 

 Pierince visit flowers very freely, it is seldom that they 

 hover about a particular plant trying each separate 

 blossom after the manner of so many other butterflies; 

 they very generally take a hurried sip of nectar and are 

 ofi", not settling again for some little distance. This 

 tendency seems to attain its maximum in such genera as 

 Eronia and Gallidryas which are the most robust and 

 swift-flying of the group. 



