GASTROPHILUS HAEMORRHOIDALIS AND OTHER BOTS. 



47 



dicated in Table XI, infested hair was placed in tubes at air tempera- 

 tures of a living room and allowed to remain until larva? were well 

 formed and ready for emergence. Some of the eggs were then tested 

 and the viability determined. A check was not kept, as the brownish 

 color of the dead larvae easily distinguished them from the trans- 

 parency of the active larvae. 



Table XI. — Effectiveness of washes upon eggs of Gastrophihis intestinalis, 

 Aberdeen, S. Dak., 1915-16. 



Date 



eggs 



treated. 



1915. 

 Sept. 

 Do. 



1916. 

 Sept. 7 

 Do.... 

 Do.... 



Do.... 



Do.... 



Do.... 



Sept. 9 



Do.... 



Do.... 



Insecticide. 



Refined petroleum. 

 do 



Sept. 

 Do.. 

 Do.. 

 Do.. 

 Do.. 

 Do.. 



Do.. 



Sept L. ; 



Do.i. 



Do.i. 

 Do.i. 

 Do.i . 



Do/^ . 



Kerosene 



1.35 per cent phenols i — 



2 per cent nicotine sul- 

 phate. 



Carbolic acid 2 per cent 

 phenol. 



Lard 



N itrobenzine gas 



Carbolic acid 2 per cent 

 phenol. 



Kerosene . 



0.135 per cent phenols 



1 1 Nitrobenzine gas . 

 ....do 



.do. 



0.054 per cent phenols 

 Kerosene 



2 per cent nicotine sul- 

 phate. 



2 per cent carbolic acid. . . 



Kerosene 



Carbolic acid 2 per cent 

 phenol. 



0.054 per cent phenols i . . . 



Kerosene 



Carbolic acid 2 per cent 

 phenol. 



0.054 per cent phenols i . . . 



Ex- 

 posure. 



Minutes 

 6-18 

 18-31 



Hours. 

 24 

 24 

 24 



24 



24 

 25 

 5 



29 



4 



10 

 25 

 26 

 25 

 26 



26 

 24 

 24 



25 

 147 

 146 



117 



Num- 

 ber 



larvae 



ex- 

 amined. 



Mortality of larva?. 



Dead. 



Living. 



Doubt- 

 ful. 



Remarks. 



Engine oil, No. 1. 

 Do. 



Reddish brown in color. 



2 larvae yellow in color. 



5 dead larvae yellow in 

 color. 



3 dead larva? yellow in 

 color. 



18 larvae very active. 



38 larvae very active. 



i A proprietary compound of cresol in combination with resin soap. 

 2 Eggs not well incubated were treated and larvae removed Sept. 21. 



In the tests with larvae removed from the eggs it was observed 

 that the minimum period causing death by contact was 1 minute 

 with pine tar 1 part and kerosene 2 parts. The ease with which 

 either of these can be obtained suggested a study of these and similar 

 substances. 



It will be observed that kerosene, which is commonly reported 

 to be in use by farmers, even at an exposure of 147 hours, had prac- 

 tically no effect upon larvae. When eggs upon hair were rubbed 

 they more readily yielded to hatching and apparently the larvae were 

 more active than from any similar treatment. The kerosene seemed 

 to facilitate the emergence of the larvae. While it was ineffective 

 against well-developed larvae, it was thought that upon freshly 



