INSECTS INJURIOUS TO SMALL GRAINS 125 



of the insect annually, the adults of the first generation' differing 

 considerably in appearance from those of the second. To the 

 farmer they will all look like minute or large, shining black ants, 

 with or without wings, their legs more or less banded with yellow, 

 and having red eyes. Individuals of the first generation emerge 

 in April from the outstanding straws and stubble. They are 

 very small, most of them are females, and many are wingless. 

 The females deposit their eggs in the young wheat plants, the 

 stems of which at this time extend but little above the sur- 

 face of the ground. The egg is placed in or just below the 

 embryonic wheat head and the larva or worm works within 

 the stem, usually causing a slight enlargement. When the 

 worm is full grown it will be found in the crown of the plant, 

 having eaten out and totally destroyed the embryonic head, 

 its body occupying the cavity thus formed. 



11 The females which deposit these eggs, being small and fre- 

 quently wingless, are in no way fitted for traveling long dis- 

 tances. The larva or worm is of a very light straw color, indeed 

 almost white, with brown jaws. These worms develop very 

 rapidly and, as they feed 



on the most nutritious part || 'I a \ 



of the plant, they become 

 robust and larger than 

 those found in the mature 

 straw in late summer. In 

 May the larvae become full 

 grown and pass at once 

 through a short pupal 

 stage. The pupae are at 

 first the same color as the 

 Iarva3, but later change to a 

 a shining let black. In Fia.106. Thewheatstraw-worm: method 

 r j J.T. f 11 j i of oviposition of female of summer form : 

 a tew days the iully devel- 0> f erna i e i nse rting her eggs; ?>, section 

 oped insects gnaw circular of wheat stem, showing egg; c, and 

 i T , ,, f ovipositor, d: c, egg, greatly magnified, 



holes through the walls of (A er Ril ^ y ' an ' d Webster, U. S. Dept. 



the stem and make their Agr.) 



way out. These adults are much larger and more robust than 

 the individuals of the first generation and arc provided with 

 fully developed, serviceable wings. That they make good use of 



