CIRCULAR NO. 20. 



moved northward and eastward, almost without check. This condition 

 could not last. There are everywhere multitudes of little insects which 

 can not live on vegetable matter and which must have insect food. 

 From time to time some crisis has happened in the existence of one 

 or another of these little creatures and it has had to try strange food. 

 It is but natural that many of them have been attracted to such a com- 

 mon insect as the boll weevil. 



PREYING INSECTS. 



These minute insect friends do their work in several ways. At 

 present the most important of them are the little fire ants (so-called 

 on account of their sting, which gives a burning sensation), which 

 abound in the cotton fields, exploring every inch of ground and plant 

 in search of insect prey. They are very active little creatures and seem 

 to have learned to recognize the presence of boll weevils in the fallen 

 squares. When one is located the discoverer summons a squad of her 

 fellows and they gnaw their way into the square and remove the weevil 

 entire or in pieces to their nest, where it is quickly consumed. On ac- 

 count of this habit these little ants are called PREDACEOUS or PREY- 

 ING insects. One of these fire ants is shown, greatly enlarged, in 

 Figure 2. This little ant, which occurs all over Texas and Louisiana, 

 should not be confused with the Argentine or so-called "New Orleans" 

 ant, which has become such a household pest in Southern Louisiana. 



Figure 2. A Are ant (Solenopsis aeminala), which is an important enemy of the 

 boll weevil (After Hunter & Hinds. Bur. of Entomology, U. S. Dept. of Agr. 



PARASITIC ENEMIES OF THE WEEVIL. 



The most interesting enemies of the boll weevil are about fifteen 

 species of very small wasp-like insects, which fly around the cotton 

 fields until they find a cotton square with a live weevil larva in it. 

 Then they lay an egg in the square on the weevil, and fly to another 

 square to lay another egg. They have a sharp apparatus called an 

 "ovipositor," for depositing their eggs, with which they can easily 

 pierce the square. These eggs hatch in three or four days and the 

 little grubs commence to feed on the boll weevil larva. The weevils 

 die and their enemies grow and finally develop into full grown insects 

 like the one which laid the eggs. One of the most important of these 

 wasp-like parasites is shown, greatly enlarged, in Figure 3. 



