78 



ENTOMOLOGICAL SOCIETY OF ONTARIO. 



Fig. 78. 



returning to London and making search, I found its exact counterpart on an enlarged 

 scale in " Saunders's Insects Injurious to Fruit," page 185, which is here reproduced, 

 Fig. 78. 



'During the next day, the Earpalus larva rested quietly, two m orms seemingly 

 being enough to satisfy its cravings for one day • whilst the remaining worm was very 

 restless, no doubt from want of food. In the evening, being in com- 

 pany the army worm was introduced in (he conversation, when I re- 

 membered that I had the box in my pocket, I took it out to show the 

 worm, but there was not the vestige of a worm left, and the Uarpalus 

 larva was rushing frantically round in the box in search of more. I 

 kept it that night to see if it would attack the chrysalid, but it did 

 not, so I gave it its liberty next morning in consideration of the good 

 it might do. 



A great deal of romance has been written upon the army worm. 

 Its sudden appearance in vast and destructive hordes is well calculated 

 to arouse the imagination of those who are usually totally indifferent 

 to, and wholly ignorant of the habits of insects ; consequently the 

 movements of the army are to them perfectly mysterious. We read of 

 their coming, no one knows how, or from where, of their always 

 travelling to one particular point of the compass. Of their following 

 a leader who directs their movements ; and who gives the signal for 

 their advance by a wag of his head ; and much more of the same sort. 

 The army worms come from eggs, like all other insects, which in this 

 case are laid near the roots of grasses by the moth Leucania unipuncta; 

 and may be feeding there in great numbers when young, without attracting the slightest 

 attention. It is not until they are well grown that they acquire their great powers of 

 destruction, and then the field in which they were born may not be able to sustain all of 

 them ; when the necessity to travel to other localities in search of food is forced upon 

 them. The only really mysterious thing about their movements is, that they should keep 

 together in a body, and go in the same direction in search of food, instead of, as is usual 

 with caterpillars, each going in the direction that its fancy leads, independently of the 

 others of its kind. This gregarious habit is indeed very wonderful. But food is their 

 objective point of travel, not any particular one of the compass. 



There is another destructive insect that is endowed with this peculiar habit of 

 travelling all together in one direction in search of food, namely, the migratory locust in 

 its mature state ; and a consideration of its mode of progress in desolating a region, may 

 assist us in forming an idea concerning that of the army worm. When we read of an 

 invasion of locusts into a locality where there were none before, they are always repre- 

 sented to us as coming down from the air above, ravenously hungry, as if it had been 

 their first stopping place lor food on a long journey, a few at first, then a dense mass, 

 sufficient at times to obscure the light of the sun, gradually becoming thinner, then 

 passing over, not leaving any living green thing behind them. This appearance, although it 

 may be misunderstood by the onlooker, is nevertheless quite in harmony with the actual 

 facts of their progression. Supposing a field well stocked with locusts who have just 

 developed mature wings and a prodigious appetite, find their food supply exhausted, and 

 it has become needful for them to go elsewhere for more. The field next to them is 

 untouched, those close to it enter, those behind them follow, whilst those at a distance 

 who are as eager for food and in as great a hurry to obtain it, rise on the wing and fly 

 over the feeders and alight just beyond them, their peculiar gregarious instinct compelling 

 them to feed in crowds, -so that those that entered the fresh field first, find themselves 

 surrounded by a multitude which has devoured everything before they get enough > 

 hence they in turn find it necessary to rise on the wing and make for the front again to 

 obtain more and so having started they proceed ; and the deeper and denser the 

 advancing host, the further they have to fly to reach the front, and the more of them 

 there are on the wing at one time, the higher some of them have to rise in the air to get 

 over the others ; and when we read of their coming down in such numbers and such 



