112 Capsid Bugs cmd Apjyles 



somewhat recently been adopted as a food plant, and that this change 

 has brought about an alteration in the time of appearance of the insects. 

 However this may be, it is evidently useless to speculate on the biology 

 of these species without further observations and this paper may be 

 concluded by a reference to the very meagre notes on " treatment " 

 which have been gathered. 



Since the damage is done soon after the insects leave the egg it is 

 evident that any treatment by means of spraying must be carried out 

 at exactly the right time, and the spray must of course be one which 

 kills by contact. Crosby, in America, found that paraffin emulsion, 

 whale-oil soap and lime sulphur were of little service. Preparations 

 of nicotine and soft soap gave fairly good results and were recommended 

 with the caution added that the trees must be very thoroughly drenched 

 with the wash. The spray was to be applied both before the blossom 

 opens and after it falls. In England, a wash of this nature has been 

 found partly successful, but in one case no benefit whatever resulted, 

 the reason given being that the bugs hatch out over a long period. In 

 this case, both species were present and if 0. marginalis is later in 

 appearing than P. rugicollis, it is probable that this explanation is 

 correct. The possibility of a winter wash against the eggs is hardly 

 worth considering, for apart from the failure of winter washes against 

 insect eggs in general, it will probably be found that the eggs of these 

 bugs are deeply imbedded in the bark of the twigs, quite out of the reach 

 of all sprays. The problem of dealing with these bugs in some ways 

 resembles that of the apple sucker {Psylla mali) and is likely to be as 

 difficult. At present, therefore, the only treatment which can be 

 suggested is a spray of soft soap and nicotine, or possibly soft soap 

 and quassia, but success will depend on a nice estimation of the exact 

 time to apply the wash, and the thoroughness with which the application 

 is made. Cases such as this bring out clearly the need for further 

 experiments in insecticides, especially in " contact " insecticides, with 

 the object of finding an efficient substitute for the expensive nicotine 

 and if possible of increasing the number of reagents from which to 

 choose. 



REFERHNCES. 



1. Theobalt). Wye College Journal. Reports on Economic Zoology for the years 



1910 (p. 108), litll (p. 115), 1912 (p. 24). 



2. Colling E. Journal of Economic Biology , vol. vii. p. 04. 



3. Taylor. Journal of Economic Entomology, vol. i. p. 371. 



4. Crosby. Cornell University Bulletin 291. 



5. See reforonco 4 above. 



6. Caesar. Entomological Society of Ontario, 1912, p. 102. 



