REPOET OF THE ENTOMOLOGIST. 307 



tTTO dozen chiysslidea — a large proportion. I liad 75 chrysalides iu a box in summer; 

 about 50 came out moths ; most of tlio others could not escape from and perished in 

 the dried leaves. I saw not a parasite of any kind. 



An encouraging statement concerning the extensive parasitism of an 

 early brood (the third) is contained in a letter from Mr. Trelease of July 

 24, 1879. He stated that at that time nearly one-half of the half-grown 

 worms iu the fields under his observation bore the eggs of one of the 

 Tachina parasites. One-half is certainly a large proportion, but he re- 

 iterates it vvith exactness in his notes, and stands ready to vouch for it. 

 It seems not at all unlikely when we consider the numbers in which the 

 northern siJecies of Tachina occur in fields ravaged by the northern 

 army- worm. In a field which was black with these worms I have searched 

 for hours without finding a single unj)arasitized full-grown worm. Nine 

 hundred and ninety-nine out of a thousand bore the white eggs of the 

 destroyer. 



These few points will be sufficient to give a more accurate idea of the 

 importance of the natural enemies of the cotton-worln. 



REMEDIES. 



Preventive measures. — The most important of the preventive 

 measures which can be adopted is the encouragement of the natural 

 enemies of the cotton -worm. Detailed accounts of these have been 

 given in a previous section ; hence, but little remains to be said here. 



The most practicable thing which can be done in this direction is the 

 protection by law of all the native insectivorous birds. An incalculable 

 amount of injury has been done by the indiscriminate destruction of 

 birds by the freedmen since the close of the war. In addition to the 

 protection of the native species, others might be introduced. But here 

 very great care must be exercised, else more harm than good may be 

 accomplished. No species should be introduced the habits of icMch are 

 not thoroughly understood. We wish to call particular attention to this 

 point, as many planters have urged us to aid in the introduction into 

 the cotton States of the English span-ow, a species the importation of 

 which into the Northern States has been pronounced a calamity by nearly 

 all of the American ornithologists. 



The encouragement of the insect enemies of the cotton- worm, though 

 less practicable than the protection of birds, is not less important ; for 

 this reason, great care has been taken to figure and describe all the pre- 

 daceous or parasitic insects which destroy the cotton-worm. It would 

 be worth the while of every planter to become familiar with the appear- 

 ance of the more common of these, and instruct his hands not to injure 

 them. In those cases in which hand-picking of the pupae of Aletia is 

 employed, much good can be done by taking care not to destroy the 

 parasites contained in them. The pupae, when collected, instead of be- 

 ing destroyed should be placed in barrels or boxes covered with coarse 

 wire gauze or other netting. In this way the parasites which emerge 

 from the pupae can be allowed to escape through the meshes of the net- 

 ting, and are thus enabled to go on with their destruction of the pest; 

 whereas the moths which mature, being larger, cannot escape, and perish 

 in their prison. Some idea of the importance of this precaution may be 

 gathered from the results of an experiment already cited, in which it 

 was found that of 1,721 pupae of tlie fourth brood, nearly 10 per cent, 

 were parasitized. Or what is more to our purpose, there were bred from 

 these pupae 44 large parasites {Fimpla, Chalcls, and Tachina), and an 

 immense number of small parasitic flies belonging to the genus Phora. 

 It must be remembered that the later broods of Aletia contain a larger 

 percentage of parasitized individuals. 



