280 



Cuba to collect parasites, where lie found four species. The egg- 

 parasite, Trichogramma minuUmi, Riley, already occurs in Louisiana. 

 The Tachinid fly, Euzenilliopsis diatrame, Towns., usually emerges 

 from the larvae, but sometimes also from the pupae of this moth. 

 The puparia of this parasite were shipped in tin boxes containing 

 damp sphagnum moss and cotton, and these were packed in card- 

 board cases. About 33 per cent, arrived in New Orleans alive. They 

 travelled better when ventilation holes were made in the boxes. 

 In New Orleans the parasites passed through two, possibly three, 

 generations. As they pass the winter in a dormant state the attempt 

 to breed them all the year round in heated greenhouses was not 

 successful. Should this Tachinid become established in Louisiana, 

 it will prove a very valuable asset to the control of D. saccharalis. 



The other two parasites found were the Hymenoptera, Bassus 

 (Microdus) stigmatenis, Cress., and Apanteles sp., but as these were 

 very rare, it was decided not to attempt to introduce them without 

 further study. 



Fl NT (W. P.), Turner (C. F.) & Davis (J. J.). Methods in Entomo- 

 logical Field Experimentation. — J I Econ. Entom., Concord, N.H.^ 

 xii, no. 2, April 1919, pp. 178-183, 1 plate. 



Various methods are described that were tested in Illinois to obtain 

 accurate records of infestation of wheat fields by Hessian fly [Mayetiola 

 destructor] ; these included the picking method, the method of selecting 

 • — at haphazard— five Hnear yards and examining all the plants in each 

 yard, and the similar selection and examination of half a square 

 yard. Tables show the results of the counts made by the different 

 methods both in 1917 and 1918. These indicate that the above- 

 ground appearance of plants should be used only in generalising infesta- 

 tion, such as heavy, medium or light. The picking method is useful 

 in autumn scouting work, when estimating Hessian fly infestations, 

 but is practically useless in the spring and also in the autumn, if the 

 wheat-plants have tillered abundantly. For experimental plots where 

 simplicity, accuracy and comparison of results are essential, the linear 

 foot method is undoubtedly the most satisfactory, and at least ten 

 linear feet should be taken from each plot where counts are required. 



In the matter of estimating yields various methods have also been 

 studied. It is the opinion of some agronomists that reliable records 

 can be obtained only by harvesting the entire plots. Others hold 

 that accurate yields can be obtained by harvesting such small areas 

 as one-thousandth of an acre. It is hoped to obtain the use of a 

 portable threshing outfit in order to make a comparison of the different 

 methods. In the meantime, the method used to obtain the yields 

 in wheat-sowing experiments in connection with Hessian fly is to 

 select five typical square yards from each plot. The wheat from 

 this area is bagged, transported to a central point and there threshed, 

 weighed and graded, the grain being tested and its quality recorded. 

 It is not claimed that this method is the best possible, and in point 

 of fact it seems to give records above the actual yields, but it provides 

 a fair method of comparison, which is the main consideration. 



Estimates of injury by insects are frequently difficult to determine. 

 Where large areas are completely destroyed by such insects as white 



