1640 THE BUTTERFLIES OF NEW ENGLAND. 



quite another affair. It would seem as if attempt at something striking 

 had been made. Many of these are figured on pLites 43 and 45. They 

 usually appear as patches or oblique dashes of peculiar scales covering 

 veins and membrane indiscriminately, but usually, and in our native butter- 

 flies always, occupying the middle of the front wing, and crossing the 

 median veins olilirpiely near their base. These dashes are variously 

 formed, but the scales which compose the most striking external feature are 

 much larger than the ordinary scales, are black, and frequently partially 

 erect. They may also differ in various parts of the patch itself, and may alter 

 their character abruptly ; for instance, some comparatively huge and bril- 

 liant scales may occupy the middle line, and be buttressed by a multitude 

 of minute, crowded, lustreless scales ; or there may be at one point a sort 

 of whirlpool of large party-colored scales, imbricated, in the most regular 

 fashion, like the normal scales, and, beyond them again, a multitude o{ 

 the minute, crowded, lustreless scales. These peculiarities, however, 

 must be studied with a glass ; the naked eye may indeed discern that the 

 patch difiers in different insects, but the general effect in all alike is a 

 variously formed velvety patch or oblique streak of black. 



Now, the object of all this, however important it may possibly be as an 

 ornamental appendage, is primarily concealment for the androconia, which 

 are quite out of sight, roofed in by the large imbricated scales of opposite 

 sides, which it would seem the insect must have the power of parting to 

 allow the scent to escape, just as the costal fold can be opened, flung open 

 probably, by some muscular movement at tlie base of the wing. In this 

 discal ])atch likewise there is a certain regular distribution of the special 

 scales, and these have their characteristic types. 



BIBLIOGRAPHY. 



Aurivillius, C. Ueber sekuudare gesclilechtscharaktere nordischer tagfaiter. 8°, Stockholm, 

 1880. 

 Miiller, F. A prega costal das Hesperideas. 4° Kio, 1878. 

 Scudder, S. H. Antigeny or sexual dimorphism in butterflies. 8° Boston, 1877. 



Table of species of Erynnis, based on the egg. 



Flattened surface at summit of egg about one-third the diameter of the base, with a distinct 

 limitation sassacus. 



Flattened surface at summit of egg almost one-half the diameter of the base, with indistinct 



limitation luetea. 



Other species unknown. 



Table of species, based on the caterpillar at birth. 



Ranged bristles very much longer than any one of the shorter sections of the abdominal seg- 

 ments sassacus. 



Ranged bristles shorter than one of the shorter sections of the abdominal segments metea. 



Other species unknown. 



No material exists for any table based on the mature caterpillar or the chrysalis. 



