MOTHS AND BUTTERFLIES. 461 



pillars reach maturity after five moults, being at that time nearly one inch and three- 

 fourths in length, of a black color, with a yellow line along the middle of the back. 

 There are ten tubercles on each segment, with a cluster of hairs arising from each. The 

 hairs on the back of the segments are black, but on the sides they are brown. The 

 pupa is three-fourths of an inch long, smooth, shining black, and enclosed in a loose 

 cocoon, which the insect spins in some protected place. 



JVbla sorghiella is a troublesome pest, which infests the heads of sorghum in the 

 gulf states, spinning its silken threads over and among the seeds in such a manner as 

 to form a compact mass in which the whitish excrements of the caterpillars are 

 scattered. These caterpillars form numerous delicate tubes through which they pass 

 from one seed to another, feeding more especially on the germ, but sometimes consum- 

 ing nearly the entire seed. They are very active when disturbed, and at maturity 

 descend to the ground, where they spin a fine, delicate cocoon covered with particles 

 of wood, bark, or other convenient material. The moths, according to Professor 

 Riley, emerge late in July or early in August, and expand a little less than half an 

 inch. They are of a silvery-white color, with a row of three tufts of scales below the 

 costa on the fore wing, and a yellowish-brown, curved band across the Aving towards 

 the outer margin. The mature caterpillar is half an inch long, of a yellowish or light 

 greenish yellow color, with a small, yellowish head. It has a sulphur-yellow line along 

 the middle of the back, and a rather broad, brownish, longitudinal stripe on each side. 

 Each segment has a transverse row of six tubercles with short, stiff, brownish-tipped, 

 yellow bristles, and a similar tubercle at the base of each leg. 



The family ZYGJENID^ comprises those moths which have the head of moderate 

 size, and free from the thorax, with ocelli present. In the typical genera the antennas 

 are simple, and slightly enlarged in the middle, or partially clavate towards the tips. 

 The thorax is moderately stout, and longer than broad. The abdomen is short and 

 thick, generally twice the length of the thorax. The wings are long and narrow, 

 though often triangular, and the cell is so long that the nervules are shorter than in 

 the allied families. The costa of the fore wing is comparatively straight, the apex 

 much rounded, and the outer edge full, and half or two-thirds as long as the hinder 

 edge. The hind wings are generally one-half longer than wide, though sometimes the 

 length is twice the width. The legs are rather stout, but well proportioned, and 

 thickly scaled in the typical species ; but in one group they are armed with long, sharp 

 spines, and the femora are hairy, while the fore tibia3 are densely pilose. The scales 

 in this family are fine, powdery, and scattered thinly over the surface, often leaving 

 naked spots on the wings. Some of the species fly in the bright sunshine, others by 

 night. 



Dr. Packard includes Castnia and its allies of South America, and Synemon with 

 its allies of the Australian region, in this family. These last insects resemble the but- 

 terflies in many respects ; but in their general structure, habits, and early stages, so far 

 as known, they are more nearly allied to the typical ZygasnidaB than to any other 

 family. The caterpillars in this family differ considerably, some being naked, and 

 others clothed with hair ; and while some species spin a dense cocoon, others make none 

 at all. Some spend the winter in the pupa, and others hibernate in the caterpillar state. 

 The Zygcenidas are most abundant in tropical and warm temperate countries, very few 

 extending to the Arctic regions. 



o -J 



Harrisina americana is distributed throughout the middle part of the United 

 States, from east to west. The wings, which are long and narrow, expand nearly an 



