134 EEPOKT UPON COTTON INSECTS. 



wet or dry season ? In the answers to this question great unanimity 

 was found. With but few exceptions, the general opinion seems to be 

 that wet years are the most disastrous caterpillar years. 



This fact (for such it undoubtedly is) has been always accounted for 

 by the fact that wet weather produces a rank and succulent weed, of 

 superiornourishing power to one dwarfed and dried by continued drought, 

 and by the fact that in hot dry weather many worms are actually killed 

 by the heat of the sun and by the oven-like heat of the earth when 

 marching is attempted. 



Another point, intimately connected with this last, is the one that the 

 low, damp parts of a field are the ones where the worms always appear 

 first in spring. This may be accounted for by the probable fact that on 

 damp parts of a plantation the early cotton grows faster than on the 

 drier parts : nectar is earlier secreted from the foliar glands ; the hiber- 

 nating moths are attracted by the nectar to that part of the field, and con- 

 sequently more eggs are there laid. 



Both of these facts have, however, been accounted for by a plausible 

 theory, first publicly put forth by Mr. H". A. Davis, of Cherokee County, 

 Texas, in 1866 or 1867. In a letter of recent date, Mr. Davis states his 

 theory in the following words : 



Hon. WM. G. LE Due, 



Commissioner of Agriculture : 



DEAR SIR : Much has been said and written, and valuable time and money ex- 

 pended in study and experiments to learn the nature and to destroy that great enemy of 

 the cotton planter of the South the cotton-worm. 



The most generally received opinion is that wet seasons produce the worm, and 

 warm dry seasons kill them. The caterpillar makes its appearance in the warmest 

 climates and at the hottest season of the year, and the warmer the climate and the 

 hotter the season the greater their thrift and multiplication. If they appear in May 

 it will in this latitude require at least 32 days to pass through all their different 

 stages ; but from July 1 to September 15 not more that 28 days are necessary. 



That wet seasons are favorable to their protection and multiplication we will not 

 deny ; but it is from other causes. 



My observations, beginning in 1866, have fully satisfied me of the fallacy of the 

 above theories and as thoroughly convinced me of the fact that the Formica (little red 

 ant) is the great friend and protector of the cotton planter of the South. They are 

 found by the million in almost every spot of land on which the cotton plant is grown 

 over the regions of country liable to the ravages of the worm. In other portions of the 

 South not infested by the worm I have noticed this ant in but limited numbers, 

 showing the wisdom and goodness of the Divine Distributor for our good. Herewith 

 I forward you specimen ant. 



When the weather is favorable all the day long, they, true to their ancient and 

 proverbial reputation, are at work climbing every plant and traversing every leaf, 

 especially the under side where the egg is deposited, and the young worm makes its 

 appearance with the same instinct to find and devour that is found in the miller that 

 deposits them there. They devour the eggs and the worm (until about two days old) 

 and finally make havoc of the chrysalis. The discovery was accidental. I had been 

 watching and experimenting to learn the nature and habits of the worm, to ascertain 

 the periods of their different stages, and to learn the period from one brood to another, 

 and the probable number of worms that might be expected from each miller, and on 

 this occasion I was gathering chrysalides to see what was the probable number then 



