OBSERVATIONS ON THE LIFE HISTORY AND BIOLOGY 

 OF AGROMYZA LATERELLA ZETTERSTEDT. (Diptera).* 



P. W. Claassen. 



In the spring of 1916, while studying the interrelation of 

 insects to certain swamp plants near Ithaca, New York, my 

 attention was called to the occurrence of galls on the common 

 wild blue flag, Iris versicolor. The plants then were from six 

 to ten. inches high, with three or four leaves out. The galls 

 were always found on the outer leaf of the leaf-bundle, the 



Figure 1 



affected leaf ceasing to grow. This formation of the gall and 

 the subsequent cessation of growth of the leaf very often affects 

 the second or next inner leaf in a pecuHar manner; the tip 

 remains caught in the gall for some time, the growing leaf is 

 bent out and in its rapid growth produces a number of wavy 

 or undulating folds. Fig. 1 shows a photograph of a small 

 group of plants with several galls and the characteristic appear- 

 ance of the second leaf. 



*Contribution from the Entomological Laboratory of Cornell University. 



