THE EGG PARASITES OF THE COFFEE BUG IN KENYA COLONY. 197 



This experiment, it may be remarked, gives us the evidence of 14 cases that a 

 single mating sufficed to produce a similar proportion of females to that found in 

 parasites reared from eggs from the field. 



(5) Partheno genetic Reproduction. 



In a series of 20 experiments females to which no male had ever had access were 

 given coffee bug eggs. All the conditions defined for the series of ten mated pairs, 

 other than those relating to mating, were observed, and the times of the life-cycle 

 were not different from those obtained in that series. From these 20 females 442 

 offspring were obtained, all males ; 482 eggs went blue, but 40 did not produce 

 parasites. The largest number from one female was 40. In other experiments 

 described under (6) and (7), in some of which the parent parasites were fed and the 

 number of offspring was larger, all the parasites reared were males. In no single 

 case under observation has a female been produced parthenogenetically. 



(6) Parasitisation of Eye-spotted Eggs. 



In two experiments with unmated females all the conditions of the series described 

 above under (2) were fulfilled except one {h) — for all the 50 eggs, which had been 

 laid in the laboratory and protected from parasites, showed eye-spots when they 

 were given to the parasites. In these two experiments 28 parasites were bred, thus 

 showing that eye-spotted eggs can be parasitised. Just how late such eggs can be 

 successfully attacked by the parasites has not been determined. 



When eggs are parasitised which do not show eye-spots, the change of colour 

 from white to blue is fairly sudden. Often on one day such an egg will be of the 

 typical white colour, and on the next of the typical blue. But when eye-spotted 

 eggs are parasitised the change of colour is more gradual. After a few days — a shorter 

 time than that in which eggs not eye-spotted would require to go blue — the colour 

 becomes a dirty brown, which deepens with successive days. In these two experi- 

 ments the eye-spots gradually faded and eventually could not be distinguished. 

 The eggs then took on the typical blue colour, but it was not so easy as with eggs 

 not eye-spotted to say exactly when the change took place. 



(7) Number of Eggs parasitised by fed Females, unmated. 



In each of five experiments one unmated female was given thirty different Antestia 

 eggs every three days. The average number of offspring parasites, all males, obtained 

 in these experiments was 51 , the maximum being 83. These numbers are considerably 

 higher than those obtained under the conditions of the experiments described above. 



(8) Variations in the Length of the Life-cycle. 



In hot weather the life-cycle is passed through more quickly than when it is 

 cooler. Particulars are given in Table II (p. 201) of a series of experiments in which 

 Antestia eggs, laid in the laboratory and protected from parasitisation, were placed for 

 a short time in a tube containing numerous parasites. The minimum times for the 

 life-cvcle in the different experiments varied from 25 to 62 days. For meteorological 

 data,^ see Table IV (p. 201). 



It will be noticed that the time elapsing before the eggs go blue is always about 

 a third of the period of the parasite's life-cycle within the egg. 



B. Telenomus iruncativentris. 



The facts obtained in life-history work on Telenomus will be discussed in much 

 the same order as for Hadronotus. Unless stated otherwise, the conditions in 

 corresponding experiments on the two species were the same. 



(1) Length of Life of Parasites. 



The average length of Hfe, for both males and females, was about 4 days when 

 they were given water only. When fed on diluted golden syrup the average length 



