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and 1888, with the astounding number of 2033 papers on 
economic entomology, written by himself, in collaboration, or 
under his direction. Though many are mere recapitulations 
or brief notes, the most cursory examination serves to show 
that their united contents form a mass of observations on the 
ways and habits of insects and of practical advice which has 
never been equalled. Kiley was not the first entomologist to 
approach economic questions by a scientific method instead of 
the rough rule-of-thumb treatment which too often passes for 
economic entomology. That honour belongs to Eatzeburg ; 
but it is likely that Riley's attitude towards such questions 
was entirely his own, that he owed nothing, at least in his 
early career, to the work of his predecessor, and that the 
combination of a painstaking, accurate and logical habit 
of mind in research with great practical readiness in 
turning his results to account, was entirely responsible for the 
success of his labours. The work done by and under him 
has followed Eatzeburg' s lead in showing that the successful 
treatment of insect pests depends on the scrutiny not only of 
the insects' habits, but of the obscure -circumstances which 
determine their capacity for multiplication and their relations 
to their environment, in short, of the factors which control 
their struggle for existence ; and when these are grasped, 
that the problem of their destruction may be attempted with 
some measure of success. As examples of many such 
inquiries conducted on right lines may be cited the celebrated 
investigation into the Coccid, Icerya purchasi, with the 
subsequent importation against it of the Lady-bird, Vedalia 
cardinalis, and the Eeports on the Locusts of North America. 
The practical side of the work done under his auspices is 
clear to anyone who has studied the details of the spraying 
and fumigating apparatus, the arsenical washes and kerosene 
emulsions which have been introduced in America. An apt 
instance of Eiley's love of labour and readiness to study 
insects in the field is found in his successful working-out, 
during a holiday in England, of the life-history of Phorodon 
humuli and its heteroecism on the hop and damson. This 
was held as a vague belief by some English entomologists, 
and probably would have remained as such to the present day 
