250 



INSECTS 



practically no specific natural enemies, found condi- 

 tions so materially changed in its favor that it increased 

 by leaps and bounds, followed the trail of its food plants 

 to the east, and in a few years over-ran the entire area 

 of potato cultivation. 



It was first described in 1824; it had become abun- 

 dant enough to demand the attention of the economic 



FIG. 115. Colorado potato beetle: a, egg; 6, larvae; c, pupa; d, adult beetles. 



entomologist in 1869, when Riley wrote concerning it 

 and the methods to be adopted for its control. I still 

 remember the joy that possessed me when, for the first 

 time, in 1874, I found on Long Island a patch of pota- 

 toes with the insects present in all stages. They had 

 arrived earlier, but I had not been fortunate enough to 

 get within their range previously. As nature works, 

 all this is so very recent that nothing has yet developed 

 in the way of an effective natural check. It is rarely, 

 however, that an insect is so marvellously favored by 

 the changed conditions produced by man. Usually it 



