Salt-marsh Moth Caterpillar

There are five to seven instars. The following description is based on Hinds (1904), who observed five instars in Texas. Upon hatching the larvae are about 2 mm in length, brown in color, and bear numerous long over the entire length of the body. During this stage, and the subsequent instar, larvae feed gregariously on the lower leaf surface, usually failing to eat entirely through the leaf. Larvae attain a length of about 10 mm during the first instar. Second instars display longitudinal stripes, usually brown, yellowish, and white, and the body hairs become darker. Larvae attain a length of about 15 mm. During the third instar, larvae become darker, but a consistent color pattern is not apparent. Larvae attain a length of about 30 mm. In the fourth and fifth instars, larvae maintain the same general appearance as earlier stages, but grow to a length of about 45 and 55 mm, respectively. Larvae usually are dark, but sometimes are yellowish brown or straw colored. The larvae are marked by long body hairs, and these also vary in color from cream or grayish to yellowish brown to dark brown. Although they are decidedly hairy, the hairs are not as dense or as stiff as those found in woollybear larvae. Duration of larval development was 24 to 37 days. In contrast, Young and Sifuentes (1959) and Capinera (1978b) reported six instars in Mexico and Colorado, respectively. Development time of the six instars was about 3, 2, 2, 2, 3, and 8 days, respectively, for a larval period of 20 to 22 days, depending on diet. However, some studies have reported longer larval periods, up to about 45 days.