THE SWISS' SPECIES OF THE GENUS HESPERIA. 49 
was, superficially, most distinctly alveus, the only other possibility 
being that it was a hybrid alveus x armoricanus, an idea which was 
fostered more by the extraordinary date of capture than the appearance 
of the specimen. As it was, unfortunately, a ? , anatomical proof of 
its identity was difficult to come by, so I sent it to Prof. Reverdin. 
Unfortunately, even in such expert’ hands, the dissection was not quite 
a success, and failed to give the desired information ; nevertheless, the 
Professor remarked that the superficial characteristics were so pro- 
nounced that he felt no doubt whatever that the specimen was alveus. 
He further informed me that two other $ specimens of alveus, 
captured in May, had come to his notice, one from Locarno, the other 
from the Grand Saleve, which latter was taken by M. Rehfous of 
Geneva. When one recalls that Prof. Reverdin receives material from 
all over the Palearctic Region, and that, in spite of this, previous to 
the capture of my specimen, only two others had come to his notice, ° 
it will be readily realised how extremely rare this spring emergence of 
individuals of alveus must be. This then, being the ease, the fact that 
these few specimens have been taken, and the probability that in time 
others will be recorded, does not appear to be any sufficient reason for 
regarding alvens as anything but a single-brooded species. 
July, as has been already noted, is, in the majority of localities, 
the normal time of emergence of the species, but I have taken it on a 
few occasions in late June, more often (curiously enough) in sub- 
Alpine regions than lowland ones, and once at over 5,000 feet, but only 
three times in more than single specimens. Once, on June 28rd, at 
Verossaz, above St. Maurice, where I took two gs; once in the 
Ueschinen Tal above Kandersteg, when I took three 7s, on June 30th, 
and once at Lenzerheide, in the Grisons, where, between 5,000 feet 
and 5,300 feet, the species commenced to emerge on June 2ist, and 
_from the 23rd on was seen daily in increasing numbers. Other June 
specimens that I have taken come from Vernayaz, Caux (this latter on 
June 10th), and the hills behind Clarens. In these latter localities, 
between my capture of the single specimens and the subsequent 
emergence of the rest of the brood, there was a period varying from a 
week at Vernayaz to nearly three at Caux. In early seasons it is 
probable that the species is often out by the end of June, and I hear 
from Prof. Reverdin that in some southern localities, such as St. 
Martin de Vésubie, the time of emergence is late June, but otherwise, 
in his experience, it is always July. At altitudes over.5,500 feet it is 
safe to say the species will never be found before the first week in July. 
But, although alreus in the plains appears no earlier than it does some 
thousands of feet higher up, it also (strangely enough) remains longer 
on the wing in its mountain habitats. The duration of the period of 
flight of the species is difficult to ascertain exactly, on account of its 
very irregular emergence, and necessitates constant observation for 
quite two months in one locality, if any useful result is to be obtained. 
In its lowland habitats the species is normally over by early August, 
but some years it is often to been seen well on in the month, while on 
one occasion I have taken a 9d in quite fair condition on September 2nd. 
The longest period of time I have noted alveus on the wing is seven 
weeks. This was at Lenzerheide (Grisons), between 5,000 feet and 
5,300 feet, from June 21st to August 9th, at which date, when I left 
the locality, it was still about in some numbers, and would certainly 
