FIELD BOOK OF INSECTS. 



The Common Blue is also called pseud- 

 Lycaena ladon arg i i us an d the Spring Azure. Small, blue 

 butterflies are pretty sure to be this species, if they have 

 no tails; but it is a creature of many fashions, some of 

 which are shown in Plate XXXIII. These forms are 

 partly sexual, partly seasonal (there are two broods 

 around New York), partly climatic, and probably partly 

 something else. The larvae feed on the flowers of 

 various plants including Cornus, Cimicifuga, Actinomeris, 

 Spir<za, and Ceanothus. Ants attend the larvae and, 

 by touching them with their antennae, induce the larvae 

 to excrete from abdominal glands a sweet fluid which the 

 ants drink. 



PAPILIONIDyE 



Both sexes of the Swallow-tails and their relatives have r 

 normally, six good walking legL,. The chrysalids have a 

 silk supporting strap around them but it -does not hold 

 them as closely to the surface upon which they are fixed as 

 in the Erycinidag and Lycaenidae. 



This undesirable immigrant, the Im- 

 Pieris rapae por ted Cabbage-butterfly (Plate XXXIV), 

 is the only butterfly which seriously injures our crops. 

 It was accidentally introduced from Europe in 1860 at 

 Quebec and in 1868 at New York; in twenty years it 

 covered about half of the United States and Canada; now 

 no cabbage patch from coast to coast is too small or too 

 isolated for rapes. The well-known green larva feeds on a 

 variety of cruciferous plants but likes cabbage best 

 Thank you! There are usually three broods a season, 

 winter being passed as a chrysalis from which adults 

 emerge early in the spring before the native cabbage 

 butterflies are stirring. These early spring adults are 

 smaller and less heavily marked than the summer form, 

 which is here illustrated. Some individuals (variety 

 immaculata) are without the black spots on the upper 

 side of the wings but the underside of the hind wings are 

 yellowish as in the typical form. 



134 



