ON EMERGENCE OF THE GRYPOCERA .AND RHOPALOCERA. 69 
Ist to 20th July: epiphron, gorge, liyea, aglaia. 
15th July to 10th August: tithonus (=eros), apollo, lycaon, cordula.. 
End of July to late August: virgawreae, damon, dolus, tyndarus. 
15th August to beginning of September: alveus, carthami, neoridas. 
A study of the modes of emergence with respect to altitude in a 
vast and varied mountain range like the Alps would doubtless furnish 
interesting data, but I must leave it to those who have a better know- 
ledge of that region than I have. I must limit myself to some 
observations on the only locality which I have explored sufficiently 
well during various years: the Baths of Valdieri’in the valley of the 
Gesso (Maritime Alps). The altitude is the same as that explored by 
Querci in the Sibillini, but the climatic conditions are very different, 
both on account of the more northern latitude, and of the neighbour- 
hood of the great Alpine glaciers. The fauna offer ‘¢ high-mountain ” 
characteristics much more marked on account of the morphological 
appearance of the races and on account of the much greater number of 
species proper to the great altitudes, and of the very small number of 
individuals or the total absence of many species of the plains. The 
favourable season for the perfect insect is limited to little more than 
two months, and that in which larval activity is possible to little more 
owing to the early and late snowstorms. Therefore the Baths of 
Valdieri precede very little that zone of highest altitude at which the 
normal development of Grypocera and Rhopalocera is possible, and 
which igs inhabited almost exclusively by its own proper species, 
analagous to the arctic. Turati and I have found this glacial 
fauna a little higher than the Baths, in the Vallasco Valley, at 1700m. ; 
in peninsular Italy it does not exist at all, not even on the tops of the 
mountains which surpass that height, and the corresponding zone is 
inhabited by mountain species, which in the Alps descend much 
further down. It is natural therefore that in conditions with such 
special environment emergence should take place very differently from 
what happens in the mountains of peninsular Italy. The phenomena 
produced by altitude as regards the broods no longer consist of simple 
reduction of the number of individuals or in suppression of one or two 
broods in the sense above indicated, but consist in the reduction to one 
single annual cycle of all the species (except a few rare trigenerates) 
owing to the impossibility of producing a greater number during the 
very short favourable season. Besides, whilst in other climatic 
conditions the annual species are partly precocious and partly tardy, 
here their emergences all group together so as to adapt themselves to 
the short period above mentioned, and between the beginning of such 
extremes as cyllarus, cardamines, euphrosyne on the one hand, and of 
virgaureaée, tyndarus, neoridas on the other, there remains but little 
more than three weeks, from the end of June to the end of July. 
Apropos of this I must allude to the really notable delay which 
meleayer suffers, emerging much later than the other species (in the 
second half of August) instead of ina middle period compared with 
the others, as in the plain (July), or in the Sibillini (end of July to 
late August). Ido not know of other examples of this phenomenon, 
but I have observed that in Tuscany this same species tends to 
reproduce it: in the lower hills of Florence it emerges in July; 
