THRIPS ON THE ONION. 333 



received from Japan via Paris, where they must have been ino-c- 

 culated with the germs of this much-dreaded insect plague. 



Pasteur and Quatrefages, and others whose names are illus- 

 trious as investigators, have been commissioned by the French 

 Government to study the causes of this disease, and it now 

 thought, that, following out the suggestions M. Pasteur — the re- 

 sult of profound studies on this subject — if healthy eggs be 

 selected by aid of the microscope, and those infested with the 

 parasitic fungus be destroyed, silk culture will be again restored 

 in France and Southern Europe. As the result, a single silk 

 raiser, whose worms this year will produce 32,000 ounces of 

 eggs, hopes next year to have 100,000 ounces, and the prospect 

 of a profit of a million of dollars ! It should be remembered 

 that this remarkable result is due, primarily, to the most abstruse 

 researches upon microscopic plants by specialists, for the pure 

 love of science. Their cloister studies, put to practical ac- 

 count, saves the destruction of one of the largest agricultural 

 interests in Southern Europe. In like manner had the general 

 government or individual States, encouraged the entomologist 

 and botanist in their studies, and caused them to be turned to 

 practical account, we should not have had to give up the culti- 

 vation of wheat in the northernmost States ; our cotton crop 

 could perhaps have been doubled, and our garden and field 

 crops have regularly yielded a steady return to the producer. 



In England, where less attention has been paid to practical 

 zoology than with us, increased interest is taken in this subject. 

 A botanist has just been appointed to the Royal Agricultural 

 Society, and an entomologist will soon be elected. 



INSECTS INJURIOUS TO FIELD CROPS. 



The Onion Thrips. — About 'the middle of August my atten- 

 tion was called by Mr. B. P. Ware of Swampscott, to his serious 

 loss of onions from the attacks of a minute insect. The leaves 

 were observed to suddenly turn yellow and wilt, and the plant 

 died. In this way large patches became infested and turned 

 yellow, until in two or three days these prolific insects spread 

 over the whole field. They seemed to increase most rapidly dur- 

 ing the unusual dry, hot weather that we experienced about the 

 middle of last August. On the 11th of August a whole acre was 

 thus cut off. Mr. Ware informed me that the onion plants have 

 been more or less infested in this way for some fifteen years, but 



