81 



and after the failure of the ,£;rapo in 1850, became the principal article of export. In 

 1670 the exports reached 6,000,0001b, worth on the spot $3,200,000. In 1844 the 

 French succeeded in introducing it iato Algeria, and the Dutch have introduced it 

 into Java. 



The literature on this family is most meagre, and, in fact, until Prof. Comstock 

 published his article in the United States Department of Agriculture Report of 1880, 

 nothing systematic of any consequence had been done. This gentleman is making a 

 thorough investigation of this difficult but interesting subject, and as it is necessary to 

 have a large series of specimens, it is in the hands of everyone to assist him, for if any 

 person who noticed a plant infested by these insects were to send a note and specimens to 

 him I am sure he would be glad to receive them, and they might possibly do much good 

 by putting into the hands of a specialist, species unknown to science, upon which he would 

 experiment in the same careful and thorough manner which is so manifest in all his work. 

 It is satisfactory to know that after a great number of experiments. Prof. Comstock has 

 found that, for all these insects the most effectual remedy is that very economical one — 

 common soap. 



6 (EN.) 



