REPORT OP THE ENTOMOLOGIST. 283 



1878 circular, ^vhich he had rctaiued until this time to make further 

 observations. He says : 



Tlie common ant ruaintaius an equilibrium when it is not too ice/. TLo ant will 

 destroy the eggs unless the rainy weather keeps it in its retreat. This is the reason 

 that a dry season is never a caterpillar one. 



Upon receiviug this we wrote to Mr. Brown for further particulars, 

 and received the following reply : 



Dear Sir: In answer to yours of the 29th instant in relation to cotton-worm and 

 whether the common ants were destructive to it, would reply that I have observed 

 the ant on the cotton plant and apparently seaehing it for prey. During sunny 

 "weather they are numerous, every cotton plant having several crawling over it, and 

 they do destroy the eggs of the cotton-worm, for I have seen them stop a,s soon as they 

 came across them and eat and carry them away. In wet weather the ant has retreated 

 to its quarters and few can be found anywhere in the cotton field, and the caterpillars 

 have undisturbed opportunity to multiply and increase. 



We have the worm hero now in force, and would be greatly damaged, but its first 

 appearance was two weeks too late. And I have noticed that my theory of the ant 

 has had additional substantials for its support, for during four or five sunny days 

 there is a decided increase and activity on the part of the ant and a marked decrease 

 of the same on the part of the worm. 

 Yours, respectfully, 



JAMES C. BROWN. 



WiLLET, Barnwell Couxty, South Carolixa. 



This same idea is again expressed by Mr. Douglass M. Hamilton, of 

 Saint Francisville, La., in his report, in which he says: "Ants of many 

 kinds are found preying on them in good tceather^ but not in bad, and this 

 is the reason given why the worm increases so much faster in rainy, wet 

 weather than in dry and fair weather." 



Mr. Wm, V. Keary, of North Bend, Cheney^ille, parish of Rapides, 

 Louisiana, December 17, 1877, in writing to J. Curtis Waldo, says : "The 

 cotton-caterpillar requires a wet season to accumulate, as such weather 

 is destructive to its natural enemy, the ant, and also an insect called 

 the ichneumon," &c. 



The following extracts from Mr. Trelease's note-book are of interest in 

 this connection : 



September 10, 1879.— On the second place, where 100 acres are eaten out entirely, I 

 find thousands of nearly-grown aletias crawling in every direction. In wet places 

 they are not so much molested by ants, for there are few of these ; but on dry, sandy 

 places I find ants killing many larvae. * * * Can it be that aletia first appears in 

 wet places because the ants are not so numerous there as on high, sandy places? 

 Early I found caterpillars on both bottom and ridge land. Were not most of the lat- 

 ter killed? This theory must bo taken in connection with that of the nectar, for 

 certainly there are more eggs laid in wet ground. Can it not be that this is partly 

 due to the fact that more moths are excluded in such places and lay their eggs without 

 leaving them ? 



The one sentence, ^'■Early I found caterpillars on hotJi bottom and ridge 

 lands,'^ forms a strong argument for IMr. Davis's theory. 



And now as to our own conclusions : K it can be shown that the num- 

 ber of cotton- worms actually killed by the ants is as great as stated by 

 the upholders of the theory, then there can be no doubt but that it ac- 

 counts for observed facts. But what evidence we have collected as to 

 the efficacy of the ants as destroyers of the cotton-worm seems hardly 

 sufficient to wan-ant us in unqualifiedly supporting so broad a theory. 

 We can safely say, though, that the agency of the ants is one of the 

 prominent factors in bringing about the dry- weather scarcity or wet- 

 weather abundance of the cotton-worm. The most important time for 

 the ants to be pursuing their good work is among the early broods of 

 worms—in May and June. Every worm killed at this time saves the 

 cotton from hundreds later. The numbers of individuals in the earlier 



