THE COLORADO POTATO-BEETLE. 



707 



my seventh report : " Those who have watched the gradual spread of 

 this potato-beetle during the past seventeen or eighteen years from its 

 native Rocky Mountain home to the Atlantic, and who have seen how 

 lakes, instead of hindering its march into Canada, really accelerated 

 that march, can have no doubt that there is. danger of its being carried 

 to Europe. Yet I must repeat the opinion expressed a year ago and 

 which has been very generally coincided in by all who have any 

 familiarity with the insect's economy that if it ever gets to Europe it 

 will most likely be carried there in the perfect beetle state on some 

 vessel plying between the two continents. While the beetle, espe- 

 cially in the non-growing season, will live for months without food, 

 the larva would perish in a few days without fresh potato-tops, and 

 would, I believe, starve to death in the midst of a barrel of potatoes, 

 even if it could get there without being crushed ; for, while it so vora- 

 ciously devours the leaves, it will not touch the tubers. The eggs, 

 which are quite soft and easily crushed, could, of course, only be 

 carried over on the haulm or on the living plant ; and while there is 

 a bare possibility of the insect's transmission in this way, there is 

 little pi'obability of it, since the plants are not objects of ccramercial 

 exchange, and the haulm, on account of its liability to rot, is not, so 

 far as I can learn, used to any extent in packing. Besides, potatoes 

 are mostly exported during that part of the year when there are 

 neither eggs, larvoe, nor potato haulm in existence in the United 

 States. There is only one other possible way of transmission, and 

 that is in sufficiently large lumps of earth, either as larva, pupa, or 

 beetle. Now, if American dealers be required to carefully avoid the 

 use of the haulm, and to ship none but clean potatoes, as free from 



Fig. 4. Bogus Colorado Potato-Beetle. 

 a, c, eg^s : 6, 5, larva; <", lieetln : </. left-wins: cover, enlarsred, showing marks and punctures; e, 

 leg "enlaraied. Colors ; of e^^', pale-ye'.low ; of larva, cream-yellow ; of beetle, black, yellow, 

 and brown. 



earth as possible, the insect's transmission among the tubers will be 

 rendered impossible; and when such precautions are so easily taken, 

 there can be no advantage in the absolute prohibition of the traffic in 

 American potatoes. As well prohibit traffic in a dozen other com- 

 modities, in many of which the insect is as likely to be imported as in 

 potatoes. The course recently adopted by the German Government, 



