Herbert W. Miles 171 



ii. methods. 



In order to arrive at soijie definite conclusion as to what insects are 

 found feeding and wintering in grasses, examples of the various species 

 dug up from headlands, hedgerows, waste ground and arable fields, were 

 taken into the laboratory and examined, each shoot being cut open for 

 careful scrutiny. The date, locality, species of host plant, and the number 

 and variety of insect stages present were recorded for further considera- 

 tion. Of the insects found some were preserved in spirit, others kept in 

 captivity, if larvae or pupae, for examination in subsequent stages, 

 while many were dissected for microscopic examination. 



While the laboratory work was proceeding the crops growing on the 

 College Farm were kept under observation and, where they were attacked 

 by any insects of the species found feeding amongst grasses, data as to 

 cultivations, date of sowing and infestation were secured. In this con- 

 nexion particulars are included of the attack by Frit Fly on winter 

 wheat in the early part of 1920. 



Special note was taken of insects found sheltering in the plants 

 examined, since definite information concerning the means whereby 

 many insects pass the winter is lacking. 



With regard to root-feeders such as "wireworms" and "Leather- 

 jackets" the difficulty of taking them actually feeding presented itself, 

 but where symptoms of attack in grasses and corn crops were identical 

 it was considered justifiable to draw conclusions. 



The foregoing may be considered as the winter methods, those obtain- 

 ing in the summer period varying in that less time was spent in the dis- 

 section of grasses and more in observing the attacks of leaf-feeding and 

 leaf-mining insects under field conditions. Here again arose the difficulty 

 of the root-feeders and night-feeders, so that evidence of the larvae 

 having eaten and their proximity to the attacked plant when taken 

 were noted and inferences drawn. 



III. SOIL AND LOCALITY. 



Most of the observations were made on the College Farm, where there 

 are two main types of soil, viz. the heavier loams merging into clays 

 and the fighter loams emerging into soils of sandy texture. Geologically 

 these types are represented by the Lower Red and Mottled Sandstone 

 and the Pebble Beds, both of the New Red Sandstone formation. The 

 locaHty is approximately 220 feet above sea level and is exceptionally 

 free from smoke of factory, foundry or town. 



