1532 THE BUTTERFLIES OF NEW ENGLAND. 



order to fix for each species its probable range. The plotting of these 

 localities upon maps brings these facts more vividly before the eye and permits 

 a readier comparison ; but in addition to that it brings out in full relief 

 some striking anomalies in the distribution. Doubtless in most cases 

 these anomalies can be referred to imperfect knowledge, since they often 

 only extend further in an isothermal direction the well known range of the 

 species ; but in other cases it is difficult to account for the presence of a 

 given form so far removed from all its other known habitats. 



As an instance of the former class may doubtless be cited such a species 

 as Oeneis jutta, which is known from localities as far apart as the Rocky 

 Mountains of British Columbia and Hudson Bay, but from no part of the 

 intervening area ; in this instance the known localization of the butterfly to 

 morasses of peculiar nature sufficiently accounts for its not having been 

 found in the country lying between these two points, where it would seem 

 from its presence in the Rocky Mountains that it must unquestionably 

 exist. But quite another matter is the discovery of Cercyonis nephele in 

 the Athabasca region bordering Hudson Bay, when it has not been found 

 in any of the intervening area between this and southern Manitoba, where 

 not a few collections have been made which would be likely to contain so 

 easily captured and striking an insect. Or, still better, observe the case 

 of Satyrodes eurydice, a species which, but for a single capture in the far 

 northwest by Great Slave Lake, would be unknown excepting in the north- 

 eastern United States and the parts of Canada adjoining ; here the species 

 has been discovered a thousand miles from the western limits of the previ- 

 ously known range. 



We have taken these examples entirely from one limited group, the 

 Satyrinae. What is true of them is true also of numerous other species, 

 to mention a few of which in serial order, we call attention, first, to the 

 extraordinaiy fact of the occurrence of Polygonia satyrus along the valley 

 of the St. Lawrence in two or three different localities, when it had pre- 

 viously not been known east of the Rocky Moimtains. Junonia coenia is 

 even a more startling case, for it has been taken in a single instance north 

 of our boundary in the Rocky Mountain region, whereas, by its previously 

 known distribution, it was justly looked upon as a southern butterfly, its 

 nearest point to this capture being central California, at least six himdred 

 miles away. The occurrence of each of our New England species of 

 Argynnis in distant parts of the Rocky Mountain region, north and south, 

 is explainable bv the fact of the extension of each of these species nearly 

 or quite as far as the eastern limits of this region, or at least to the western 

 borders of the prairie region, and it may perhaps be questioned whether in 

 all these instances the species be rightly determined. 



In Hypatus bachmanii we have an instance of a different nature, not so 

 striking perhaps, for we have to deal with an insect remarkable for its 



