INSECTS INJURIOUS TO STORED GRAINS 



193 



easily push aside when it comes out in the spring, and then covers 

 itself with a fine silken web. At this time the caterpillar is 

 usually fully grown and is about one-fifth of an inch long, of a white 

 color, with the head yellowish and harder, and having six jointed 

 legs in front, a series of four pairs of fleshy pro-legs along the 

 middle, and another pair of soft legs at the end of the body. 

 With warm spring weather the caterpillar changes to a pupa ? 

 and about the time that the wheat comes into head the adult 

 moth emerges. As soon as it emerges, whether outdoors or in a 



FIG. 142. The Angoumois grain-moth (Sitotroga cerealella) : a, eggs; b, larva 

 at .work; c, larva, side view; d, pupa; c, moth; /, same, side view. 

 (After Chittenden, U. S. Dept. Agr.) 



barn, the moth at once flies to the grain-field, where the eggs are 

 deposited. The exact time at which the moths emerge varies, 

 but occurs some time late in May or in June. The moths quite 

 closely resemble the clothes-moth often found flying about houses. 

 The wings are quite narrow, and when expanded measure about 

 one-half an inch from tip to tip, being of a yellowish or buff color, 

 marked with black. The eggs are laid in the longitudinal channel 

 on the side of the grain. Each female lays from sixty to ninety 

 eggs in lots of about twenty each, one lot thus being about enough 

 to infest the kernels of a head. The eggs hatch in from four to 

 seven days. The young caterpillars are at first very active 

 and soon find tender places and bore into the kernels, leaving 



