13 



were noticed in the territory which separates or adjoins the local- 

 ities mentioned. 



The ravages of this insect have been such, in many instances, 

 as to occasion great loss to the farmer ; and hence no little anx- 

 iety is felt in regard to its appearance in future years. On this 

 point, there arc some important facts which should tend to lessen 

 our fears. It is undoubtedly an annual insect ; that is, its period 

 of existence is limited to a year, though it is not certain that some 

 of them do not pass the winter in the chrysalis state. It is not at 

 at all like the Cicada septemdecim, or seventeen-y ears' locust, as 

 some have erroneously supposed. Yet it is remarkable that it has 

 seldom, if ever, prevailed to a great extent on the same ground or 

 in the same neighborhood, two years in succession. The reason 

 for this is not altogether clear. There are some points in regard 

 to the habits and economy of the insect, which, owing to the com- 

 paratively Uttle attention it has hitherto received from skilful en- 

 tomologists, are not thoroughly understood. During the past sea- 

 son, however, several competent gentlemen have devoted consid- 

 erable study to it, and the result will undoubtedly be that the 

 former mysteries will be unravelled. One interesting fact, how- 

 ever, in connection with its not appearing where it was numerous 

 the former year, may be mentioned. It is frequently, perhaps 

 generally, pursued by parasites, by which great numbers are de- 

 stroyed. In some investigations made the past season by the 

 Chairman of your Committee, it was found that at least two species 

 of parasites attacked the worm in this neighborhood. These par- 

 asites are ichneumon flies. They sting the worm and deposit an 

 egg in iLs body. This does not immediately kill the worm, or 

 hinder it from developing itself to such a degree in the larva state 

 that it passes in the usual way into the chrysalis — the specimens 

 contain the parasitic egg, presenting, at first, no external differ- 

 ences from others. But in due time there emerges from the shell 

 of the chrysalis, instead of an army-worm moth, a wasp-like fly. 

 The egg which was deposited in the worm hatched there, and the 

 parasite, gradually developing itself, fed on its victim ; but, as if 

 actuated by instinct, did not destroy it till the shell of the chrysa- 

 lis was perfected, which served as a habitation for the parasite, 

 while it consumed, as food, what was the body of the worm, and, 

 if unmolested, would have become a moth. Mr. Walsh, of Illi- 

 nois, who has written a valuable paper on the army-worm, states 

 that in some localities where this insect prevailed to a great ex- 

 tent the past summer, its parasitic enemies were so numerous that 

 it will not be likely to appear in numbers sufiicient to do much 

 damage next year. "Whether this was the case in this section, we 

 cannot positively say. We are at present unable to suggest any 

 measures for destroying the army-worm, or of preventing its rav- 



