90 The Field Naturalist's Quarterly May 



life-histories of these high mountain species, you will find, in 

 nine cases out of ten, that they are unknown in their entirety, 

 and sometimes altogether. A female will occasionally oblige 

 in the box wherein she is imprisoned ; a close search of the 

 grasses growing among the boulders may disclose a batch or 

 a single egg. But the larvas are not to be found so easily — 

 much less bred. They are night-feeders, and hybernate for 

 the most part in the larval state, which accounts for much of 

 our ignorance regarding their metamorphoses. 



Such discovery, however, is the true province of the field 

 naturalist, and even in the life-histories of some of our own 

 little band of butterflies there are still blanks to be filled in 

 by close and careful observation. Minute study and rearing 

 larvae are hardly possible in a brief holiday, but here I would 

 earnestly recommend to all collectors, whether old or young, 

 the desirability of keeping notes, not only of mere captures, 

 but also of such facts as appear remarkable with regard to 

 the several species taken ; for in this way it is that miss- 

 ing links are discovered. 



To return to glacialis, there is generally the added element 

 of danger in the chase. Like all its race it loves to lop gently 

 over the dizziest precipices, and, once startled, is not easy to 

 come up with, save by diligent stalking. A little experience, 

 however, teaches the wisdom of striking after, and not at, a 

 butterfly upon the wing, and I have found that the surest 

 method is to keep the sun and wind, if possible, in front of 

 your net, so that the shadow may not disturb the butterfly 

 when it is at rest, nor the wind assist its escape, as it in- 

 variably will on a steep mountain-slope. Select the top of a 

 warm sunlit gully, and wait there if, as is probable, insects 

 are ascending it ladder fashion, stopping a moment to toy 

 with the saxifrage and other rock plants, but always working 

 upwards. In this way you will often get far better results 

 than by stumbling over the loose stones and shifting earth 

 which are more sparsely tenanted. 



The Alps of Switzerland and Central Europe possess no 

 less than twenty -six species of the genus Ercbia, but the 

 separation of them as often as not is a matter of great 

 difficulty, from the confusing manner in which one species 

 apparently merges into another. The three highest fliers, 



