About Colias chrysotheme (Esper, 1777)
Colias chrysotheme (Esper, 1777) is the smallest of the three orange yellowing species found in Central Europe. It has a wingspan of 36 to 44 millimeters, and adults of the second generation are often slightly larger than those of the first generation. Females are white with a tinge of yellow-green. They can be recognized by a greenish front edge on the upper side of the forewing and yellow spots in the submarginal area; whitish forms of females are extremely rare. Males have pale yellow to orange-yellow coloration on the upper side of their wings. The upper wing edges are black or dark gray with a reddish fringe, and the species has a dark outer marginal band that is narrower on the hindwing. The orange color of male C. chrysotheme is slightly weaker than that of Colias croceus, and much weaker than that of Colias myrmidone. Yellow veins within the dark outer marginal band are visible on both the forewings and hindwings of C. chrysotheme. In comparison, yellow veins in this band are usually only present at the tips of the forewings in C. croceus, and completely absent in C. myrmidone. Both sexes have a black-brown spot in the cell on the upper side of the forewing, and a red spot on the upper side of the hindwing. The egg of this species is cylindrical with a conical tip. It is whitish when first laid, and turns yellowish before hatching. The larva is green with an interrupted white and red side stripe, though larval color can vary. The pupa is green-yellow with dark spots. This species is distributed in eastern Central Europe, specifically Lower Austria, Burgenland (at Lake Neusiedl), Hungary, and extends eastward to Romania, Ukraine, South Russia, Kazakhstan, South Siberia, Mongolia, and the Palearctic parts of China. It favors flowered meadows, sparse forests, plains, and steppe at altitudes below 2,000 m.
