THE STATE ENTOMOLOGIST. 45 



can get Army-worms, but we have more of the latter than they can 

 dispose of. 



A. E. TRABUE. 



Upon receipt of this letter, I visited Hannibal and ascertained 

 that the worm was even more numerous around New London, and 

 especially on the farm of Mr. A. McPike. 



ITS SUDDEN APPEARANCE AND DISAPPEARANCE. 



The popular idea about the sudden appearance of an insect has 

 always been an erroneous one. The ''blows" or " gentiles" iu meat, 

 " skippers" and mites in cheese, plant-lice on plants, etc., etc., are 

 very generally supposed to have a spontaneous origin, and our sud- 

 den Army-worm invasions have very generally been accounted for 

 in the same way, by those who know nothing of Nature's workings. 

 Yes, and so-called savans — will it be credited ! — have been anxious to 

 so far tickle the popular fancy as to conceive and give birth to 

 theories (such as that of larval reproduction) which were not one whit 

 more sensible or tenable. 



It is well known to entomologists, and the reader, by perusing 

 the article on "Cut-worms" in my First Report, will soon become 

 aware of the fact, that most of the larvae of our Owlet Moths (family 

 N'octuidce) rest hidden during the day and feed in the morning and 

 evening, or at night. They are all smooth, tender- skinned worms, 

 and cannot endure the scorching rays of the sun. Consequently 

 many of them live almost habitually, just under the surface of the 

 soil, while others shelter themselves under vegetable substances dur- 

 ing the day. Our Army-worm forms no exception to the rule, for 

 upon closely watching the habits of the hosts I witnessed last sum- 

 mer in the field, and of hundreds which I had confined in breeding 

 cages, I ascertained that they frequently hide themselves Cut-worm 

 fashion, just under the surface of the ground, or under the plants 

 upon which they feed. The Army-worm delights, in fact, in cool, 

 moist and shady situations, and from the passage already quoted, from 

 Mr. Kirkpatrick, where it is shown that the worms which swarmed on 

 the Cuyahogo fiats, did not attempt to remove to land a foot or so 

 higher: and from further facts recorded by Dr. Fitch, it becomes evi- 

 dent that its natural abode is in the wild grass of our swamps, or on 

 low lands. During an excessive dry summer these swampy places 

 dry out, and the insect, having a wider range where the conditions 

 for its successful development are favorable, becomes greatly multi- 

 plied. The eggs are consequently deposited over a greater area oi 

 territory, and if the succeeding year prove wet and favorable to the 

 growth of the worms we shall have the abnormal condition of their 

 appearing on our higher and drier lands, and of their marching from 

 one field to another. For just so soon as the green grass is devoured, 

 in any particular field in which they may have hatched, these worms 

 are forced, both from hunger and from their sensibility to the sun's 

 rays, to leave the denuded field. 



