REPORT OF THE SOCIETY 117 



one had to be prudent about conclusions. However by comparing the 

 quantity eaten while at liberty and that taken to escape death in prison, 

 useful information was gathered. Thus, the petunias excepted, the leaves 

 had been attacked. The insect eats very little of the tobacco and tomato, 

 but eats some nevertheless. It is evidently hunger that compels it, since it 

 abstains for five or six days. This fact I have been able to ascertain only 

 with dry leaves. At first I changed the leaves to maintain at least in part 

 the conditions of life in a state of liberty. But these leaves dried up without 

 any sign of their having been attacked. With the dry leaves the perfora- 

 tions were easier to notice on account of the decreasing elasticity of the 

 fibres. Evidently the conditions are out of the ordinary, but a conclusion 

 which has its importance forces itself upon us: The perfect insect which 

 resists famine naturally can prolong its life for a considerable time by taking 

 small quantities of tobacco or tomato leaves. It could then be transported 

 enormous distances in these very leaves and thus spread rapidly. This 

 insect which seems so awkward and heavy, gifted with wings only to drag 

 itself along clumsily would be carried instead of carrying itself. Once 

 arrived at some point, thanks to a wonderful instinct, it would journey 

 towards a potato field which would soon become its property. This would 

 explain its rapid propagation. When it came from Colorado and invaded 

 Canada itadvancedat the rate of from seventy-five to one hundred, and even 

 from two to three hundred miles yearly in spite of its clumsiness. Further, 

 it is not impossible that its life can be sustained not only by the tobacco and 

 potato but by other plants as well. This I have not tried. In any case, 

 thanks to our rapid means of transportation, its natural power of endurance 

 insures its propagation. Whither might not those have travelled which 

 lived for three weeks in empty boxes, had they been in railroad cars instead? 

 So much then for the perfect insects. 



With the larvae, experimenting is easier, since they must either eat 

 or die, and when they eat one quickly notices it. All the larvae placed in 

 boxes died, the most sturdy living but five days. Scarcely were they placed 

 in presence of the leaves before they tasted them and went away. Those 

 which had petunia leaves absolutely refused to eat and died after two or 

 three days. The others' ate some tobacco and tomato leaves, consuming 

 about one third the quantity they would have eaten of their favorite plants 

 during- the same length of time. The change did not agree with them; 

 in fact their death was caused thereby. The conclusion seems simple; as 

 long as there are ornamental tobacco and potatoes in the neighbourhood, 

 the larvae will spare the petunias, common tobacco and tomatoes. There 

 is little reason to fear them unless little by little their stomach becomes 

 adapted to the new food. Let us hope that this may not happen. 



