198 F. W. DRY. 



of life of unmated females provided with Antestia eggs was 22 days. Further data 

 for fed parasites of both sexes, some with access to Antestia eggs, some without, 

 have given a slightly less time. The greatest length of life of a female— one of those 

 provided with eggs — was 51 days, that of a male 16 days. 



(2) Life-cycle of Parasites ; Mated Females given Water only. 



The results of a series of ten experiments corresponding to those described for 

 Hadronotus under A (2) were : — 



(a) The average Hfetime of the parent parasites, as already stated, was about 



4 days, 6 days being the maximum. 

 {b) The first egg became blue after an average of 9 days, the last one after an 



average of 1 1 days, 

 (c) As with Hadronotus, the time from parasitisation of the egg to its going blue 



was about a third of the length of the development within the coffee bug egg. 

 {d) The average time between the mating of the parasites and the first hatching 



of their progeny was between 27 and 28 days. 

 {e) The total number of offspring obtained from ten females was 75, or 7.^ per 



female ; 89 eggs went blue, but 14 did not produce parasites. The highest 



number of offspring was 12. 

 (/) Of the 75 parasites thus obtained the numbers of the sexes were : — Male, 46 ; 



female, 29. 



(3) Proportion of the Sexes. 



In the series of experiments of which the results have just been given considerably 

 more males were bred than females. 



Like Hadronotus, Telenomus can reproduce parthenogenetically, all the offspring 

 so produced also being males. In the experiments under chscussion, however, the 

 act of copulation was in every case watched. In eight of the experiments one or 

 more females were produced ; in two cases all the offspring were males, numbering 

 2 in one and 9 in the other. Now it has been shown that from collections of eggs 

 from the field, for Telenomus, as for Hadronotus, the proportion of females to males 

 is about 3 or 4 to 1 . This, therefore, is the proportion of the sexes we should look for 

 in normal bisexual breeding. We therefore want to know — and this problem has 

 not been solved yet — why the proportion of females bred in the laboratory was lower 

 than that of females reared from eggs from the field. 



A limited number of experiments with mated females fed on dilute golden syrup 

 were carried out, and the following short series may be taken as a hint which needs 

 to be followed up. It so happened that three females emerged from coffee bug eggs 

 in the presence of males about a day older than themselves. After all these parasites 

 had been together about a day they were separated into three pairs of male and female. 

 Each pair was put in a tube, given 30 Antestia eggs, and provided with dilute golden 

 syrup until death. The act of copulation was not observed. From these three 

 females the offspring bred were : — Male, 10 ; female, 40. 



(4) One Male mating with several Females. 



Males in the laboratory have mated with two, three, or four females. In no 

 experiments were males given the opportunity to mate with any number much larger 

 than four. 



(5) Partheno genetic Reproduction. 



In a series of 20 experiments with unmated females the times of the life-cycle 

 were similar to those for mated females ; 159 parasites, all males, were bred from 

 the 20 females ; 196 eggs went blue, but 37 did not produce parasites ; the largest 

 number from one female was 19. In other experiments to be described under (6) 



