THE ALFALFA CATERPILLAR. 



outline, such as would enable the casual observer to recognize the 

 different forms. 



THE ADULT. 



The typical wing color of the adults is an orange-yellow with a 

 black outer border above, and a lighter yellow color on the under- 

 side with the black outer 

 border wanting. There is a 

 black discal spot in each of 

 the four wings and a double 

 discal spot of orange in each 

 hind wing. The lower sur- 

 face of the wing is the one 

 noticed when the butterfly is 

 at rest. The male (fig. 4.) 

 may be distinguished from 

 the female (fig. 1) by the 

 fact that the outer border of 

 the wings is solid black in 

 the former, but broken by a 

 line of yellow dots in the latter. A white or albino female form is 

 frequently found with other color markings, the same as in the 

 yellow form. The wing expanse is about 2 inches. 



EGG. 



The egg (fig. 5) is small, only 0.06 of an inch long, with from 18 

 to 20 slightly raised longitudinal ridges or ribs broken by cross lines. 

 It is elongated, white when laid, but turning red- 

 dish brown after the second day, and is deposited 

 upright, with 'the basal end attached usually to the 

 WW upper surface of the leaf. 



Fig. 4. — The alfalfa caterpillar : Male in the 

 adult, or butterfly, stage. One-half enlarged. 

 (Author's illustration.) 



Fig. 5. — The alfalfa 

 caterpillar : Egg, 

 greatly enlarged. 

 ( Redrawn from 

 Scudder.) 



LARVA. 



The newly hatched larva is a tiny, dark brown, 

 cylindrical object which soon after feeding takes 

 on a green color. Growth is rapid and the larva 

 (fig. 2), after having shed its skin or molted four 

 times, is a little more than an inch in length and is of a dark grass- 

 green color, with a white stripe on each side of the body, through 

 which runs a crimson line. Beneath this stripe on each segment or 

 division of the body is a black spot. There is often an intermediate, 

 narrower, broken, and less distinct white line just above each of 

 the lateral lines. This may be wanting. In some specimens a 

 black or dark green median dorsal line is also present. 

 48305°— Bull. 124—14 2 



