244 Bulletin .133- 



so that nothing but a narrow glistening white streak is visible, 

 as shown much enlarged at/" and^ in figure 69. At d and e in 

 the same figure, part of the sheath of the leaf has been removed 

 to show the eggs and their glutinous covering. Observations 

 indicate that most of the eggs are laid during the earlier part of 

 the night, the moth remaining hidden during the day. It is also 

 said that early in the season the moths prefer to oviposit in the 

 cut straw of old stacks, in hayricks, and even in old fodder stacks 

 of corn or in old bits of corn stalks scattered about in pastures ; 

 &%%?> have also been found in the spring in young grain. 



The immense numbers in which the army-worm often occurs 

 would lead one to suspect that the parent moth must be quite pro- 

 lific. Careful observation has shown this to be true, for as many 

 as 737 eggs have been found in the body of one moth. They 

 develop rather slowly in the ovaries, as a week or more often 

 elapses between the time of emergence of the moth and the com- 

 mencement of egg-laying. 



Eggs laid in the sheath of grass-blades in our cages in Novem- 

 ber hatched in from 8 to 10 days. This agrees with other records. 



Growth and peculiar habits of the worms. — A day or two before 

 the eggs hatch, the brown jaws of the developing caterpillar can 

 be plainly distinguished through the shell. 



The newly hatched worms are nearly 2 mm. (.078 of an inch) in length 

 and are of a translucent whitish color. The head is of a dark brown color 

 and the thoracic shield a little lighter. There are no indications of the 

 stripes which mark their body later. The first pair of abdominal pro-legs 

 are only about one-half as large as, and the second pair are slightly smaller 

 than, the last three pairs. All these undeveloped pro-legs bear the usual 

 booklets, but whether all are functional or not, we have not determined. 



In moving, the little caterpillars loop along like measuring-worms, and 

 when disturbed they drop themselves down at the end of a silken thread 

 which they spin, like canker-worms. As we had seen nothing recorded that 

 would indicate such a habit, we were surprised to find that for the first day 

 or two of their life the caterpillars fed upon the shells of the eggs from which 

 they had just hatched and upon the white glutinous substance which sur- 

 rounded the eggs. In each case under our observation the little worms ate 

 almost every vestige of these substances before they attacked the live grass 

 leaf. Soon after they began feeding upon the grass, this green food gave 

 their bodies a greenish color. After feeding for a few days, the little worms 

 moult or shed their skin. In the second stage of their life as a caterpillar 

 they have the same looping and spinning habits as before, and the stripes of 



