April, 'loj 



HASEMAN: CORX-EAR WOR^I 



215 



quite general feeders, especially late in the fall when they are not con- 

 fined to cornfields by any means, which makes it impossible to reach 

 them with, winter plowing. 



Life History. — The number of broods a year in Missouri has not 

 been carefully worked out if in fact there is a definite number. It is 

 a question as to just how many broods occur before the ears form. 

 After the ears form the broods so overlap that it is difficult to differ- 

 entiate them, though from our breeding records it is evident that there 

 are a number of broods a year. 



Egg. — The female ovaries contain as many as 1000 eggs in all stages 

 of development. It is not likely that all are matured and deposited, 

 though judging from the number of eggs found on the silks of one ear 

 this is not unbelievable. Egg laying must last several days. Eggs 

 are invariably placed on the corn silks the first night they are out. In 

 some cases 70 eggs have been found on the silks of a single ear. Most 

 of the eggs are stuck to the silks though some are deposited on the 

 shucks. 



Caterpillar. — The eggs hatch in about three days on an average, so 

 that the worms are at work on the silks almost as soon as polleniza- 

 tion has been completed. At first the caterpillars are too small for 

 the average eye to detect them readily. They feed at first on the 

 fleshy silks and as they increase in size, follow the silks down to the 

 grains and feed on them. Later other eggs are deposited on the tips 

 of ears so that small and large worms are found in the same ear. In 

 some cases one caterpillar may form a tunnel almost the full length of 

 the ear, though more often it destroys all the grains at the tip. 



The average length of the larval period is 18i days and has been 

 found to vary from 16 to 21 days. 



" Pupa. — ^Pupation occurs in the soil or rarely under moist rubbish. 

 The depth to which the caterpillar bores before pupating varies. In 

 breeding jars with from one to three inches of sand or soil they bore 

 to the bottom invariably. 



The pupal period in the fall varies from 7 to 18 days with an average 

 of 14 days. 



Adult. — The moth is very active and feeds on nectar of flowers and 

 juices of fruits. It flies and feeds during the day as well as at night. 

 This is especially true on cloudy days. The eggs are not all matured 

 at the same time and evidently the food taken is used in maturing the 

 eggs during the egg-laying period. ^ 



The length of the life of the adult moth was not determined except 

 in case of moths reared and confined in breeding cages. Under those 

 conditions the moths soon die, the average life being 5 days. In 

 nature the life period of the moth is evidently much longer. This 

 must be determined. 



