124 BULLETIN UNIVERSITY OF MONTANA. 



Family LYCAENIDAE. 

 The Gossamar-winged Butterflies, the Blues and Coppers. Fig. 93. 



Fig. 93. Venation of Rusticus melissa. 



The family includes butterflies of small size and delicate structure. 

 They are easily distinguished from the skippers. The body is slender, 

 the wings delicate and often brigntly colored, and the club of the an- 

 tennae straight. The antennae are nearly always ringed with white, and 

 a conspicuous rim of white scales encircles the eyes. The radius of the 

 fore wings is three or four branched. 



The blues can be distinguished from the metal-marks by the absence 

 of the costal and humeral veins of the hind wings. 



In the female the front legs are like the other legs, in the male they 

 are shorter, without tarsal claws, and with the tarsi more or less aborted. 



The caterpillars are slug-like. The body is short and broad, the legs 

 and prolegs are short and small, allowing the body to be closely pressed 

 •to the object upon which the insect is moving— in fact some of the species 

 glide rather than creep. Some of the species are remarkable for having 

 honey-tubes which can be pushed out from the seventh and eighth ab- 

 dominal segments, and through which honey-dew is excreted for the use 



of ants. 



The chrysalids are short, broad, ovate, without angulations. They 

 are attached by the caudal end, by a loop passing over the body near its 



middle. 



There are three well marked groups, which have been distinguished as 

 the hair-streaks, the coppers, and the blues. 



Key to Species. 



1. Radius of the front wings four branched, wings blue or copper color 7. 

 Radius of the fore wings only three branched, under side of wings 



with hair like streaks 



2. Hind wings wiih a long, slender, tail-like prolongation 3. 

 Hind wings with only a short projection if any 6. 



