266 SYSTEMATIC ZOOLOGY. 



The swallowtails are well-known forms of butterflies in 

 which the hind wings are prolonged into tails, whence the 

 name. The larvae of these forms are usually brightly col- 

 ored, but they are protected by a pair of 'stink-horns/ 

 which they can project at will from the region of the neck, 

 and which give off, in most cases, a most offensive odor. 



Another group of butterflies, whitish yellow or orange 

 in color, are typified by the cabbage-butterflies. We had 

 some of these which were bad enough ; but a few years ago 

 the European cabbage-butterfly came to this country and 

 became the greatest pest of all our butterflies. 



Of smaller size the most delicate of all our butterflies 



are those forms which have received the common names 



of the blues, the coppers, and the hair-streaks, from their 



predominant colors and from the ornamentation of the 



wings. 



Of larger size are the group of 'four-legged' butterflies 

 (fig. 84), so called because the first pair of legs are so small 



FIG. 84. A four-legged butterfly (Argynnis aphrodite"), under side shown 



on right. 



as to be of no use to the animal. Of these forms there are 

 hundreds of species, including the milkweed -butterflies, 

 the painted-beauty, the mourning-cloak (the first butter- 



