112 REPORT UPON COTTON INSECTS. 



substance of his neighbor, he seizes also on his house. So far as I have read concern- 

 ing this curious family of insects, this is a nondescript. As an example of these in- 

 sects called ichneumons, I may mention the Ichneumon sedttctor, or dirt-dauber, -well 

 known to everybody as that wasp-like insect which builds its clay houses on the walls, 

 and particularly in the recesses of windows, to the great annoyance of the tidy house- 

 wife. 



Thus is answered the question why the cotton-fly did not again eat up the scant 

 foliage which subsequently appeared on the stalks. This little usurper goes forth in 

 search of whom he may devour, and as soon as he finds a house built and welJ pro- 

 visioned, he seizes upon it for his posterity, which he does in the following manner : 

 When he finds a -cotton- worm, he pierces it with the instrument with which its tail is 

 armed, and deposits an egg; the cotton- worm soon spins itself up into its case, there 

 to await the period of its perfection, which never arrives, for soon the egg of the 

 ichneumon hatches, and falls to devouring his helpless companion. This work of ex- 

 termination continues until there is not a vestige of the cotton-fly left. I venture to 

 say, while I am now writing (1st of December), there is not an egg, chrysalis, or fly 

 in the confines of the United States. 



My speculations on the nature and habits of the fly have led me to adopt the fol- 

 lowing hypothesis : That it is a native of tropical climates, and never can pass a 

 single winter beyond them, consequently never can become naturalized in the United 

 States, or anywhere else where the cotton plant is not perennial, for nature has made 

 no provision by which they can survive more than ten or twelve days ; therefore they 

 must perish wherever the cotton plant perishes during a period of six months. That 

 wherever they have prevailed in our cotton-growing regions, it is when they have be- 

 come very numerous, and consumed all the cotton in their native climes, and then go 

 in search of their food in more northern climates. It is not to be presumed that this 

 happens often, but the same remark will hold in regard to the cotton-fly as it will to 

 many other insects, that owing to some unknown cause they become exceedingly nu- 

 merous, but at long and irregular intervals. The locust has already been noticed as 

 an example, and many more might be cited. I, however, will mention another to which 

 I was an eye-witness. About eighteen years ago the green or Wow fly became so numer- 

 ous that thousands of animals perished by them, also some human beings. The least 

 spot of blood, the moisture of the mouth, eyes, or nose, was sufficient to cause a de- 

 posit of eggs. Sick persons, particularly those who had not proper attention, suffered. 

 Several negro children who came under my notice fell a sacrifice to them, and it was with 

 difficulty that many others were saved. In these instances the fly deposited the eggs 

 within the nostrils, where they soon caused death by producing inflammation of the 

 brain. This fly is annual, and scarcely ever deposits its eggs on an animal, except it 

 be the victim of a running sore, but at the period alluded to above it appeared that 

 there was scarcely animal flesh enough to feed the maggots of this numerous host. 

 It is but once within my recollection that I have witnessed this phenomenon, and 

 neither before nor since have I heard of such ravages of the green fly. Why they 

 should have existed in such incredible numbers at the time referred to is a question 

 not to be easily answered 



There are three circumstances upon which I found my arguments in support of my 

 hypothesis of the cotton-fly : First. Nature has made no provision by which it could 

 survive the winter season. Second. The irregularity of their appearance. Third. 

 Their progress from south to north and from west to east. 



It may be remarked on proposition first, that all insects included within the genus 

 phalena hibernate in the state of a chrysalis, therefore it is utterly impossible for 

 the cotton-fly to hibernate in that manner, as they remain but ten days in chrysalis. 

 The fly does not hibernate, for the period of their existence is but ten or twelve days. 

 It cannot be in the state of the egg, for it is a law equally inflexible with regard to 

 this tribe, that the egg must be deposited on the leaf on which the larvae are to feed, 

 and the reason is very plain, for these larvae, when first hatched, are minute living 



