1 *24 Biology and Econotnic Sl(jnlficance of Tipula paliulosa 



examined. It had been rolled during the previous day. The crop 

 looked well, and there were no indications of Tipula attacks. Larvae 

 were again found in the most usual situation, viz., below the turf 

 clods; 40 were collected in a few minutes. Search amongst the 

 growing oat plants resulted in only one larva being found; none was 

 seen upon the surface, and none detected attacking the crop. 



On the 21st another examination was made. The weather in the 

 interval had been showery, but not very cold. The day was warm 

 and there was some wind. The field was carefully searched, particu- 

 larly for traces of larvae moving freely in the soil or actually attacking 

 the crop. They were found in the usual places below or burrowing 

 into loose "foggage" upon the surface. In a few cases they were 

 found below fiat stones at the surface. Only a very few were obtained 

 by searching the open soil around the oat plants. In this search the 

 soil was turned over with a digger and the oat plants uprooted. Some- 

 times the ground was scraped and stirred. The examination ought 

 to have discovered larvae if they were present in the soil in proximity 

 to the roots of the oat crop, and it is concluded they were absent in 

 this situation at the time of search, viz., between 10 a.m. and 12 noon. 

 The weather at the time was warm and showery, and larvae could 

 always be found amongst the decaying turf. The crop at this date, 

 notwithstanding the undoubted presence of Tipula larvae in large 

 numbers, showed no bad efiects. Up to the beginning of July, when 

 the last search for larvae was made upon this field, there was no apparent 

 effect of the presence of Tipula upon the crop. On this occasion the 

 search was effected by cutting the crop over certain areas, and sifting 

 the soil by spade and sieve. Larvae were obtained, but no pupae 

 were seen. 



It should be mentioned that in view of the presence of Tipula in 

 appreciable numbers and the possibility of an attack ensuing, a plot 

 experiment was early arranged upon the field with the object of testing 

 the effect of rolling and of some common manurial substances. The 

 experiment, though negative in its results as far as its original purpose is 

 concerned, is given here because it confirms the conclusion that Tipula 

 was not visibly damaging the crop. The field, which is surrounded by 

 trees, was rich in humic matter. Below is given a diagram of its 

 situation, and of the experimental plots together with the report of 

 Mr W. Findlay, N.D.A., Superintendent of Field Experiments. 



