Insects and Parasitic Diseases. 81 



observation. These were destroyed, and six young male '' ticks " 

 of unknoAvn ages were liberated with the nine young '' ticks " in 

 the enclosure. To prevent the escape of the fifteen " ticks," a piece 

 of muslin was placed over them and the edges fastened down to the 

 skin with liquid glue. The glue did not hold very securely, and it 

 was found necessary to rencAv the muslin daily. On May 26th three 

 of the young ''ticks" — the only surviving females — were mating. 

 On May 30th young larvae were evidently present in the abdomen 

 of all three. On June 4th three pupae were found attached to the 

 wool about ^ in. from the skin. One of these pupae had been 

 extruded very recently, as shown by its pale colour. The muslin 

 cover was then removed, and a collar or cup of buckram IJ in. deep 

 by 2| in. in diameter, and covered with a muslin top was substi- 

 tuted. The enclosure was accidently stripped off during the fol- 

 lowing night, allowing the "ticks" to escape. Thus three 

 '' ticks " which emerged on May 21st (early winter) mated five days 

 later, and extruded their first pupa when thirteen days old. 



Experiment No. ^. 



On January 12th (mid-summer) sixteen young '' ticks," about 

 twelve hours old, were liberated on a lamb housed in one of the pens 

 previously referred to. The lamb had been dipped on December 

 17th, and shorn and re-dipped on January 3rd. When the experi- 

 ment commenced the fleece was J in. long and free of both living 

 and dead '' ticks." The first examination was made three days 

 later (January 15th), when seyeral dead '* ticks " were found. The. 

 living " ticks " were not counted daily on account of the difficulty 

 experienced in finding them. On the eleventh day (January 23rd) 

 two pairs were found copulating. On the twenty-first day (Feb- 

 ruary 2nd) two pupae were found in the fleeqe. On the twenty-second 

 day (February 3rd) another pupa w^as found. On the thirty-first day 

 (February 12th) two more pupae were found. Another was found 

 on the thirty-second day (February 13th). On the thirty-ninth day 

 (February 20th) the host was carefully examined with the object 

 of finding and removing all the surviving *' ticks " and their pupae. 

 These nimibered three females, six males and two pupae. One of 

 the females contained a large larva, apparently nearly ready for 

 extrusion. These nine " ticks " were then placed on another lamb, 

 previously freed of '' ticks," for further observation (see p. 84). 

 Great difficulty was experienced in findinq: the " ticks " and their, 

 pupae, even in such short wool. In this experiment it would appear 



7 



