BLISTER BEETLES TX KxVKSAS. 21 



complete adjustment to the semiarid conditions under which they 

 thrive best than anythin^r in Rile^^'s writinfrs that have come before 

 the writer.^ 



An attempt Avill be made to apply these conclusions to field con- 

 ditions as found in western Kansas: The rainfall is most abundant 

 in spring; it gradually decreases through the summer, but increases 

 again toAvard fall. Tlie coarctate larvae that receive sufficient mois- 

 ture transform as soon as the temperature becomes favorable, and 

 usuall}^ are able to complete their life history before the moisture 

 becomes deficient. If for any reason — lack of rainfall, impervious 

 soil, or deflection of rainfall by sheltering vegetation — the soil mois- 

 ture is deficient, the coarctate larvae remain dormant. If, after their 

 appearance, the third larvae find insufficient moisture they revert to 

 the coarctate stage, and thej^ maj^ behave similarly if low tempera- 

 ture occurs. It is not known how long coarctate larvae can remain 

 dry in undisturbed cells without impairment of their vitality. 



The preceding discussion of the environmental factors responsible 

 for the phenomenon of irregular development in blister beetles is 

 intended not only to present the author's interpretation of his data, 

 but to direct attention to what he believes is a fertile field for re- 

 search on the factors influencing insect development. The incom- 

 l^leteness of the data will insure the reception of this paper as a re- 

 port of progress of work done during this period with the available 

 time and material, instead of as a definite statement of results and 

 conclusions. 



CONTROL MEASURES. 



While the writer was engaged in the work on life history and 

 habits of blister beetles, tests were made of remedies whenever an 

 opportunity occurred. The work on remedies may be considered 

 under two heads: (1) Effect of arsenicals, contact insecticides, and 

 repellents; and (2) control measures in infested fields. 



effect of arsenicals, contact insecticmes, and repellents. 



Arsenicals, 



The widely prevalent idea that arsenicals are ineffective against 

 blister beetles was left in doubt in the earlier tests of the poisons by 

 the writer; the beetles would disappear, leaving but few dead ones 

 visible. In order to learn definitely whether the beetles were killed 

 by the poisons single beet plants were sprayed with each kind and 

 beetles confined thereon in cages. 10 beetles being placed in each 

 cage. The experiment was conchictod three times during July, 1913, 

 and the data are given in Tables 1, 2, and 3, The kind of poison 



* The writer 1ms road only the n-ports of tho U. S Entomological Commission. 



