THE EGG PARASITES OF THE COFFEE BUG IN KENYA COLONY. 199 



and (7), in some of which the parent parasites were fed and the number of offspring 

 was larger, aU the parasites reared were males. In no single case under observation 

 has a female been produced parthenogenetically. 



(6) Parasitisation of Eye-spotted Eggs. 



In one experiment similar to those described under A (6) 4 male Telenonms were 

 bred in eggs eye-spotted when they were offered to the parasite. The note about 

 the change of colour of eye-spotted eggs parasitised by Hadronotns is applicable 

 to those parasitised by Telenonms. 



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



In a series of five experiments with unmated females like those described for 

 Hadronotns the average number of offspring parasites, all males, was 22, the maximum 

 being 41 . These numbers are, it will be seen, appreciably higher than those obtained 

 when the parasites were only given water. 



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



As with Hadronotns, the life-cycle is passed through more quickly in hotter than 

 in cooler weather. Table III for Telenomns corresponds to Table II for the other 

 species. The minimum times for the life-cycle in the different experiments varied 

 from 46 to 21 days. Again, the eggs go blue after about a third of the period of 

 the parasite's development within the egg has been passed through. 



C. A Comparison of the Data for Hadronotus and Telenomus. 



As has been shown, many of the facts recorded for the two species are similar. 

 The chief differences to be noted are : — 



1. In laboratory conditions, whether the parasites were fed on dilute golden 

 syrup or only given water, Hadronotns produced more offspring than Telenonms. 



2. In the offspring of Hadronotns mated in the laboratory there was an excess 

 of females like that found in rearing parasites from the field. From mated 

 Telenonms in laboratory conditions more males than females were generally 

 bred. 



3. For a given time of year Telenomns passes through its life-cycle rather more 

 quickly than Hadronotns. 



4. With hotter weather the life-cycle of Hadronotns is speeded up proportionately 

 more than that of Telenonms. (Contrast Tables II and III. Temperature 

 data are given in Table IV.) 



VII. The Bearing of Laboratory Data on Field Data. 



Much more laboratory work is needed to elucidate the facts from the field, but 

 the following conclusions or suggestions may be put down. 



1. On comparing the lengths of the hfe-cycles and the numbers of offspring per 

 female of Antestia and Hadronotns, and Antestia and Telenomns, we see that both 

 species of parasites have a quicker rate of reproduction than Antestia. But it must 

 be borne in mind that the egg-la3dng powers of Antestia are considerable. The 

 average number of eggs per female in the laboratory was 126. Nothing is known 

 of the mortality of nymphal coffee bugs in field conditions, so it is clearly possible 

 that when only some apparently small percentage — say 10 per cent. — of eggs are 

 producing Antestia, the numbers of the bug may be well on the increase. 



2. In the field, with both species of parasites, mating is the rule ; parthenogenesis 

 is at any rate rare. 



