296 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



As bearing upon this point of other Lepidopterous larvae attacking 

 the cotton-worm, we quote the following sentence from Dr. Ander- 

 son's report: "I have never seen the worm attacked by any otlier 

 insect than the gra^s-worm and then only when brought in contact." 

 Concerning this same insect, Laj)liygma /rugijyerda, of Smith & Abbot 

 (Prodenia auUimnalis of Eiley) 'Mv. Glover, in the Department of Agri- 

 cidtiu-e Eeport for 1855, p. 78, says : 



The grass-cateri)illars, when in confijiement, very often kill and devour each other, 

 and when one is maimed in the least it stands a very poor chance for its life. Several 

 intelligent planters state that when the grass and weeds are entirely devoured, and 

 no other vegetable food is to be found, they will attack each other, and feed upon the 

 etdl Living and writhing bodies of their former companions. One grass-caterpillar 

 which was kept in co)itinemeut, although furnished with an abundance of green food, 

 actually appeared to prefer to feed upon other caterpillars, no matter of what kind, so 

 long as their bodies were not defended by long bristling haii's or spines. 



It is in the next order, HY]yiENOPTERA, that we find the most effective 

 enemies of the cotton- worm. 



Wasps {Hynietiopt, fam. Ves2)ariae). — These well-kno^vn insects, as a 

 class, although they occsionaly do some harm by injuring fruit or by 

 killing honey-bees, may, on the whole, be called very beneficial insects. 

 ]!«rot only do they devour injurious insects themselves, but they also 

 store them up as'^food for their young. Concerning the actions of cer- 

 tain wasps in the cotton fields, we cannot do better than to quote again 

 from Mr. Treiease's report : 



Wasps frequent the cotton plant in considerable numbers, being attracted, like the 

 ants, in part by the nectar secreted by the plant; and there is much reason to beUeve 

 that all of the species which Aisit the plant feed more or less commonly upon the 

 caterpillar or larva of A letia. I am led to tliis conclusion by the following observations. 

 On the 8th of August, when larvae of the fourth brood of Aletia were very abundant 

 in the swamp-cotton, I saw a large red and yellow wasp— Po/isto laUicosa, Creason 

 (Plate XII, tig. 12) hunting for them. Carefully walking around the holes eateg 

 through by the caterpillars, she explored their borders with her antennae, as if fe«linu 

 for the larvae ; and each time that she found one in this way she quickly sprang after 

 it, but at the same instant the lai-va threw itself from the leaf; so that, v>'hile I was 

 ■watching her, I saw no less than eight escape, the ninth being caught and eaten. 

 Occasionally she "would stop hunting long enough to sip a little nectar from the foliaj 

 glands of the plant, and then the chase was resumed. I was very much surprised to 

 866 that she relied entirely on the tactile sense of the antennae for finding her prey. 

 Though possessing well-developed ocelli aad compound eyes, she seemed to make little 

 use of them; and repeatedly 1 saw her alight on a leaf close to a caterpillar without 

 paying any attention to him till she touched him with her antennae, when, as before 

 stated^ she' would instantly spring after it. Obser'S'ations of this sort were made sev- 

 eral times on this wasp. Another large brown wasp (PoZisfe* sp.) was also seen to 

 catch larval ^?ctia3, as alao were a yellow-jacket hornet {Fespa sp.) and a common 

 mud-dauber {Felopmm canileus, Linn.), and they all alternated hunting for caterpillars 

 with feeding on nectar. Both species of Folistea wore several times seen dying about 

 with dead caterpillars, having previously reduced them to a pulpy mass with their 

 mandibles. They were probably looking for some quiet place In which to eat them. 



Earlv in September, while watching these moths as they fed on rotting figs, I saw 

 many white-faced hornets ( Vespa niaculala) about the fig-trees. One of these hornets 

 was seen to catch a two-winged fly nearly as large as itself. After killing it, the hor- 

 net proceeded to deprive the fly of its legs and wings, which were allowed to fall to 

 the ground. The fly was thmi carried away. Under these same trees I found the 

 wings of Aletia moths, and it looks from these as though these moths are sometimes 

 killed bv the hornet ; .still, I never saw a hornet in the act of killing a moth, or with 

 the dead body of one, and I am aware their usual food is flies. 



We find, then, that certain species of wasps destroy the cotton-worm, 

 and also, without ujuch doubt, the cotton-moth. The following species 

 of so-called "wasps" were caught on the cotton plant in Alabama, and 

 in all probabilitv feed upon the \a orms : Monedula Carolina, Fab. {Hy- 

 meno^tj fam. Bemhecidae) -, Elis 4.-notata, Fabr.; Elis xAumipes, Drury 



