A METHOD FOR STUDYING THE HESSIAN FLY AND 
OTHER INSECTS.* 
By JAMEs W. McCOoLLocy, 
Associate Entomologist, Kansas State Agricultural Experiment Station. 
The following method for conducting life history studies 
was developed in connection with a study of the Hessian fly 
(Mayetiola destructer Say) and since then has been used for 
making detailed observations on the development of several 
other insects attacking the stem and leaves of various cereal 
crops. The fact that the Hessian fly larve develop between 
the leaf sheath and the stalk often below the surface of the 
ground has rendered it difficult to follow the growth of this 
stage. It has also been hard to observe the development of the 
eggs and the behavior of the larve on the leaf. 
In 1916, an attempt was made to grow the wheat plants in 
an artificial culture medium so that the entire plant would be 
exposed and accessible for observation. Plant physiologists 
have long made use of water cultures in conducting experiments 
on the nutrient requirements of plants and other physiological 
relations and it seemed possible that with certain modifications 
this method could be extended to observations on insect life 
histories. In the Hessian fly investigations, the wheat was 
planted in soil or sand and allowed to grow to a height of two or 
three inches. The plants were then removed from the soil, the 
roots thoroughly washed to remove all soil particles, and then 
placed in wide-mouth bottles of 200 cc. capacity, containing 
about 150 cc. of the water culture (Fig. 1). One plant was 
placed in each bottle, the roots being immersed in the liquid 
and the stalk kept in position by being held lightly against one 
side of the neck of the bottle with a cotton stopper. The liquid 
* Contribution from the Entomological Laboratory, Kansas State Agricultural 
College, No. 52. This paper embodies the results of some of the investigations 
undertaken by the writer in the prosecution of project No. 6 of the Kansas Agri- 
cultural Experiment Station. 
t The writer wishes to acknowledge his indebtedness to Mr. H. Yuasa for 
suggestions and aid in connection with this work. 
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