184 JOURNAL OF THE TRINIDAD 



I obtained several well-filled female ticks, and placed them 

 in glass boxes. The largest of these weighed °17 oz. and was 

 nearly an inch in length. All soon began to lay their eggs. 

 These were deposited in a heap as large or larger than the parent 

 tick, immediately in front of the mouth. In reality the genital 

 opening is situated very far forward, and each egg, as laid, is 

 passed on under the proboscis. I calculated the number of eggs 

 in several cases. It was so large as to render it almost impossi- 

 ble to count them directly ; and I accordingly adopted the plan 

 of weighing them. First of all I selected a small portion of the 

 heap and counted them carefully — usually about GOO. I then 

 weighed these accurately on a delicate chemical balance. The 

 whole mass of eggs was then weighed and the numbers easily 

 calculated. For two of the ticks the results were 17, COO and 

 over 20,000 respectively (the latter from the large tick referred 

 to above.) 



I was not surprised to learn that the time taken in depos- 

 iting all these egijs is considerable, especially as the oviposition 

 is a rather complicated act in these creatures. The larger tick 

 commenced to lay on July 30. By August 30 it had laid 13,000 ; 

 and by September 10, when it finished laying, a further 7, COO 

 had been deposited. In this case then the total period of laying 

 was exactly six weeks. At the commencement the tick was 

 fully distended, but as the time proceeded a gradual shrivelling 

 took place, so that at the end the animal would not have been 

 recognised but for the legs which stood out more prominently 

 every day. All the female ticks died shortly after the deposition 

 of the last eggs. 



Almost the whole of the 20,000 eggs hatched. To deter- 

 mine the period of incubation was difficult, and the results varied 

 a good deal. In two cases I noted the day on which the first 

 eggs were laid and that on which the first } 7 oung tick emerged. 

 The intervals were 51 and 23 days respectively. In one case 

 again the date on which the last egg was laid was noted and com- 

 pared with that on which the last ticks were hatched. The 

 period in this case was 32 days. From this it would appear that 

 the time spent in the egg varies, possibly according to the condi- 

 tion of the female at the time of removal from the animal. In no 

 case was there any indication that the ticks passed the winter in 

 in the egg condition. Those eggs which were not hatched 

 shrivelled up. 



With regard to the remaining experiments, they were 

 rendered difficult by constant absences from the laboratory. On 

 one occasion the pots were left untended for 6 weeks, and on 

 another for two months. A series of closed glass vessels were 

 placed over flower pots in which plants were growing. These 

 were in the form, of large lamp chimneys whose bases were sunk 



