136 BULLETIN 15 7, U. S. NATIONAL MUSEUM 



Genus LYCAENOPSIS Felder 



LYCAENOPSIS ARGIOLUS PSEUDARGIOLUS (Boisduval and Le Conte) 



Common Blue 

 Plate 22, Figures 1 to 4 



Occurrence. — Common, but not abundant, throughout the District. 



The common blue is a butterfly of open deciduous woods and 

 brushy land. It is especially to be found along the edges of woods, 

 in moist glades and clearings, along woodland roads and the banks 

 of wooded streams, and particularly in brushy bogs more or less sur- 

 rounded by woods. It is much more abundant in the bog at Belts- 

 ville and in the woods along Paint Branch than elsewhere. 



Habits. — The flight of the common blue is very meandering and 

 irregular, the butterfly flying from side to side, frequently doubling 

 on its tracks, and sometimes rising to a considerable height. The 

 wing beats are rather slow so that the flight appears leisurely. The 

 males wander about in a curiously languid manner, pursuing an ex- 

 tremely tortuous course. In the open they fly rather high for such 

 a small butterfly, 1 or 2 feet above the ground or grass tops. On 

 encountering a bush or a tree they will rise and fly back and forth 

 and up and down about it, sometimes reaching a height of 15 or even 

 20 feet. Their flights are as a rule much longer than those of our 

 other lycaenids. The flight of the females is as leisurely as that of 

 the males and is of the same general character. It is, however, 

 rather lower and somewhat less irregular. The females very seldom 

 rest upon the ground, or rise more than 4 or 5 feet above it. 



Though the males are rather widely distributed, the females 

 remain close to shrubbery and weedy areas in open woods or in damp 

 pastures adjacent to woods. The males, though wanderers to a con- 

 siderable extent, are much given to remaining in one particular 

 locality, constantly exploring the vicinity from the ground to 10 or 15 

 feet or more above it. 



The males are fond of sucking moisture from mud and are fre- 

 quently seen about puddles, in this region usually singly, sometimes 

 two or three together. They are also fond of carrion and filth. 



Both sexes are fond of flowers, especially white flowers. They are 

 seen most frequently on the flowers of Spiraea latifolia, as that plant 

 grows commonly in the region where they are most numerous. 



Seasons. — The common blue first appears in small numbers about 

 the last w^eek, or even about the middle, of March and becomes com- 

 mon in the first week of April. The females appear a few days after 

 the males. The butterflies continue to emerge until about the last 

 week in June and disappear shortly after the first of July. About 



