6 BULLETIN 553, U. S. DEPARTMENT OF AGRICULTURE. 



Hatching and larva molting from second deposition: 



On August 23, 10 a. m., 13 eggs of this lot had hatched and one of the larvse 

 already had molted to a nymph. On August 24, 3 p. m.j ITS eggs had hatched, 

 and 66 of the resulting larvse had molted. August 25, 2 p. m., all but four eggs 

 had hatched, and 167 of the larvse had transformed to nymphs. The following 

 day only three eggs remained unhatched, and 190 of the 200 larvse hatched had 

 become nymphs. 

 Third engorgement : 



August 26, 5 p. in., 51 females were put on a fowl for their third feeding ; 49 

 of these were recovered on the following morning. All of these were engorged 

 except one. 

 Third deposition : 



Three of these females had begun depositing at 11 a. m., August 27. During 

 the afternoon, night, and following day deposition proceeded freely. All but 

 eight of the females had begun depositing at 5 p. m., August 27. All except 25 

 had completed deposition at 7 p. m., August 28. Only one egg was found after 4 

 p. m., August 29. It will be seen that deposition began approximately 18 hours 

 ftfter the mites were placed on the host and that practically all the eggs were 

 deposited during the two days following the night of engorgement. The average 

 mean temperature during this period was 78.43° F. 

 Hatching and larval molting from third deposition : 



Two of these eggs had hatched by 8 a. m., August 29. All of those which 

 completed incubation had hatched by 3 p. m. on August 31 except one, which 

 hatched prior to 2.30 p. m. the following day. All but three eggs hatched, or 

 slightly less than 1.3 per cent. 



In a series of 10 eggs of the foregoing lot deposited between 2 and 4 p. m., Au- 

 gust 27, six hatched between 8 a. m. and 3 p. in., August 29. Two others hatched 

 during the next hour, and all were hatched at 10 the following morning. In 

 another series of ten eggs deposited on August 27, the incubation period ranged 

 from 45 to 49 hours, with an average of slightly less than 48 hours. During 

 this period the average daily mean temperature was 78.43° F. 



Molting of the larvse which hatched on August 29 to September 1 from the 

 eggs of the third deposition began on August 30, at 10 a. m., and was complete, 

 with the exception of one individual, at 4 p. in., on September 2. The molting 

 of the 10 larvse hatched on August 29 was observed and ranged from 19 to 28 

 hours, with an average of 24.5 hours. 

 Fourth engorgement and deposition : 



On the evening of September 3 the 46 remaining females were placed with a 

 fowl for their fourth feeding. Thirty-five' engorged females were recovered the 

 following morning. On September 6 deposition was completed by all but two 

 females. On September 8 all had finished depositing. One died without ovi- 

 positing, and three died soon after deposition was complete. 



Fifth engorgement and deposition: 



The remaining 32 females were put on a host for the fifth time on the evening 

 of September 8. No males had been with them since previous to the first feed- 

 ing. On September 9 22 engorged females were recovered, and all but two 

 deposited — one of these died. 



Sixth engorgement and deposition : 



The sixth engorgement of the 20 females was made during the night of 

 September 13. Fifteen of these were found engorged the following morning. 

 Of these, three failed to deposit eggs. One of these three died. 



