248 



JOURNAL OF ECONOMIC ENTO:vIOLOGY 



FURTHER DATA ON THE LIFE ECONOMY OF THE CHINCH 

 BUG EGG PARASITE 



By J. W. ]\IcCoLLOCH, Assistajit Entomologist, and H. Yuasa, Assistant in Life 

 History Studies, Kansas Agricultural Experiment Station 



At the annual meeting of this association last year the writers pre- 

 sented a paper on '^A Xew Parasite of the Chinch Bug Egg, Eumic- 

 rosoma henefica Gahan." This paper was a prehminary report based 

 on the first year's study and consequently the results were subject to 

 some modification as the work progressed. 



As the habits of the insect under consideration became better under- 

 stood and the technique of rearing and handling developed, more accu- 

 rate results were obtained. Owing to many unforeseen circumstances 

 which arose during the first year's work, the study of the life history 

 suffered several reversals and a complete life history- was not worked 

 out. During the past summer these circumstances were anticipated 

 and a continuous life histor}^ study was made. By the development 

 of certain methods of technique it was also possible to observe the 

 growth of the various stages T^ithin the host egg and to dissect out 

 the different stages for a more detailed study. 



During the past summer about 4,500 parasites were reared and a 

 large amount of data was collected. While most of the results coordi- 

 nate those obtained in 1913, some of them show considerable variation. 

 As the work of this year was carried on under more improved methods, 

 which conform more nearly with the natural habits of this insect, it 

 would seem that the results are more tj^ical of the life of this parasite 

 under natural conditions. 



HiSTORy AND Distribution 



The history of Eumicrosoma henefica began in iMa^^, 1913, when it 

 was found parasitizing chinch bug eggs in the vicinit}^ of ^lanhattan, 

 Kansas. Dming the summer of that year it was taken in sixteen 

 counties in Kansas comprising most of the area of chinch bug infesta- 

 tion. FiA^e counties have been added to this list during the past sum- 

 mer, namely, Finney, SedgT\*ick, Butler, Elk, and INIiami. 



Mr. W. B. Flint, assistant state entomologist of Illinois, reports 

 finding parasites in Hmited numbers in a few localities in that state. 

 It is probable that the parasite is also present in Oklahoma and ]\Iis- 

 souri, as it has been taken many times in Kansas within a few miles 

 of the borders of these states. 



