46 THE ENTOMOLOGIS'’’S RECORD. 
Hesperiid species, but who wish to check the identification of their 
captures in the manner described above, will doubtless find it con- 
venient to take the plates from Dr. Chapman’s articles which illustrate 
the genitalia with them for reference on their continental butterfly 
hunts. The plates of the species themselves, however, I would recom- 
mend them to leave behind. Many of the special characteristics 
exhibited by the species of Hesperia are very small, and consequently 
difficult to memorise; but enlarged figures, though theoretically an 
advantage, are very apt to be misleading. If some small spot happens 
to be in question, as being slightly different in two species, and one 
has studied the difference on a magnified illustration ; on examining 
the insects themselves, the feature we are looking for appears so much 
less pronounced than what we have been accustomed to in the illus- 
tration, and consequently so alike in both species, that a doubt is at 
once raised in our minds. But, if one has been accustomed to these 
slight differences, as shown by two natural sized figures, on seeing 
them in nature they are immediately recognised. I therefore advise 
collectors not to trust much to enlarged figures, even the perfect 
photographs accompanying Dr. Chapman’s papers. . 
Of the seventeen (eighteen if foulquieri and belliert should prove to 
be distinct) Huropean species belonging to the genus Hesperia (sens. 
restr.) no fewer than twelve are to be found in Switzerland, and they 
can all be taken in the cantons of Vaud and Valais; while several 
more occur in central and southern Europe. In spite of this many 
collectors in recording the results of their continental trips, ignore the 
existence of the Hesperias; or, just casually mention the capture of 
carthami, alveus, or malvae, the names of the other species being but 
occasionally to be seen in the pages of our entomological magazines. 
The fact remains, I am afraid, that there are but few English col- 
lectors who have taken the trouble to make themselves familiar with 
the various forms of the Hesperias, or have any definite idea what the 
names fritillum, armoricanus, onopordi, ete., should be applied to. 
This is Faun villas to be iibaed to the two following causes: firstly, 
the fact that all the systematic works on the European butterflies 
which are at present in use, were published before Prof. Reverdin’s 
researches cleared matters up, ‘and secondly, the difficulty in identifying 
the frequently occurring minor aberrations. Generally speaking, the 
typical forms of each species can readily be identified by anyone who 
has studied the genus at all carefully; but the slightly aberrant speci- 
mens which do not vary on any constant lines (but which deviate 
slightly from the type, often assuming a likeness to some other species 
while at the same time losing some of their own distinctive features) 
often become puzzling, and are almost invariably responsible for 
mistakes in identification. The range of this transitional variation is 
probably not surpassed in any other genus of European butterflies, but 
up to the present little or nothing has been published on the subject. 
I hope, therefore, the following notes (which although of a most frag- 
mentary nature are the result of careful observations made during 
many seasons) on the Swiss species in the various localities where I 
have come across them will be of interest to those who collect abroad, 
and will help to dispel some of the difficulties of identification arising 
from this transitional variation. 
There is one more point which I must mention before coming to 
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