428 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 5 



On October 5, from an egg mass collected September 12 at Argenta, 

 Ark., only three worms remained, they having gradually exterminated 

 their mates although in the presence of plenty of food. All three of 

 these worms were parasitized by Chelonus texanus and the parasite 

 larvae issued between October 5 and 8, leaving nothing but skin and 

 head shield. The hosts were about one-half inch long when killed. 

 Two of these parasites became adult between October 17 and 28, 

 after a twelve to eighteen-day period in their cocoons. 



The parasitism has a peculiar effect on the Laphygma larvae., They 

 grow and feed apparently quite normally and their cannibalistic habits 

 are not in the least diminished by the presence of a larva within their 

 bodies, perhaps they are more cannibalistic. When about one-half 

 inch long, if parasitized, the worm makes a cell. This would probab- 

 ly be in the soil under normal conditions. This cell is supported by 

 a fine meshed yellow silk cocoon. Within two days after completing 

 the cell the larva dies, and on the next day the parasite larva emerges 

 from a hole about the middle of the body. There remains nothing of 

 the host larva but the shrivelled skin and the head shield. The par- 

 asite proceeds to spin its beautiful white cocoon within its host's yellow 

 cocoon, taking one or two days for the process. The time of emer- 

 gence of the parasite seems to depend almost entirely upon the size of 

 the host. If it grows and feeds slowly, so does the parasite within. 



The premature spinning of a cocoon by the host larva long before 

 it could possibly be ready to pupate is a striking example of the results 

 of parasitism. This habit also gives added security to the parasite 

 when it emerges. 



It is also of interest to compare the two host species thus far studied. 

 Heliothis deposits single uncovered eggs and Laphygma deposits 

 great masses of eggs in several layers (several hundred to a mass) and 

 covers them with scale like hairs. 



It appears that this habit of oviposition may not be characteristic 

 of all species of Chelonus for Silvestri in describing the habits of 

 Chelonus elceaphilus Silvestri and C. orientalis Silvestri indicates that 

 oviposition probably occurs in the very young larval hosts (Silvestri. 

 La Tignola delFOlivo. Portici. 1907. pp. 154-157). 



The determination of the Chelonus was made by Mr. Henry L. 

 Viereck, to whom we owe our acknowledgments of his kindness. 



