SATVRIXAE: OENP:rs SEMIDEA, 139 



band aiulthc SI) i rack's arc Uvorowsof rouiulisli blackish fuscous spots, one on the mid- 

 dle of each sejjment; or, in tlie upper row, sometimes two spots at equal distances from 

 tlie anterior and posterior border, the anterior spot the larger. Cremaster (86 :18) bor- 

 dered anteriorly by a larire transverse, curvini;, fuscous stripe. Spiracles, with their 

 lips, l)lackisli. Lentith, 1."...") mm. ; sireatest brcadlii, <! imii. ; hciirht of tliorax, .5.25 mm. ; 

 heiii'ht of abdomen. (! mm. 



Oeneis soniidcii was first discovered about half a century ago and 

 described by Say from specimens sent him by Dr. Pickering and Mr. Xut- 

 tall of" Boston. Very few specimens seem to liave been taken since tliat 

 time (most of them found their way to Dr. Harris' cabinet) until 1859, 

 when I made my first considerable collections in the White Mountains. 

 Ascending the highest })eak on July <Sth for the ex])ress object of finding 

 this butterfly, T secured my first specimen at about a mile from the svunmit 

 near the then foot path from the (jlen ; on ascending they became more 

 abundant and although our party hastened over the ground, over forty 

 good specimens were taken, and a friend even captured seven in his hands. 

 Less than a week afterwards, in a little more than an hour's collecting, 

 fifty-nine were taken — for in its season this butterfly is exceedingly abun- 

 dant. 



G-eographical distribution. It was for a long time supposed by those 

 who did not confound this insect with an allied form found in the north — 

 in Lal)rad()r and Greenland — that it probably occupied a more restricted 

 geographical area than any other butterfly in the world, being confined to 

 the White Mountains of New Hampshire ; but it has now been discovered 

 among the Rocky Mountains of Colorado nearly tw^o thousand miles away. 

 Nevertheless the restriction of its range in the two widely separated dis- 

 tricts which it occupies is extremely interesting and instructive. In the 

 east not only is it entirely confined to the White Mountains of New Hamp- 

 shire, but even here its range is very limited. As described already in 

 this work, these mountains have been divided into three zones — mountain, 

 subalpine and alpine. O. semidea is restricted to, and occupies the whole 

 of, the highest — the alpine region from about 5,000' upward, where the 

 fierce gales and wintry ct)ld permit nothing but the scantiest vegetation. I 

 have repeatedly visited these mountains for the express purpose of studying 

 their peculiar fauna, and have lived for weeks in the woods and on the 

 barren summits at the time when the butterfly w^as most abundant ; yet I 

 have never found it outside of this area, excepting on rare occasions, when 

 a single indiAidual has been swept down the mountain side by some sudden 

 gust of wind. Many years ago I first published this statement, and no 

 exception lias been taken to it l)y the many entomologists who have since 

 frequented this district in search of their favorites. 



In the west it has so far l)cen found only in a somewhat restricted area, 

 considering the large number of high peaks which exist in the Rocky 

 Mountain region, viz. : an area in central and southern Colorado, covering 



