98 d. d'emmerez de charmoy. 



On 9th October the first parasitised larva was found, on the 20th a second, and a 

 third on 11th February 1914. In April an examination of the Insectary was made 

 and at the bottom were found but a few cocoons showing emergence holes. 



The writer was absent from the Colony from October 1913 to March 1914 and was 

 therefore unable to ascertain personally the number of insects that hatched out during 

 that period ; but as his instructions were strictly complied with, he has good reasons 

 to believe that these were very few and that the development of the insects in the 

 Insectary was impaired by causes as yet to be determined. 



With regard to this consignment there are a few facts that deserve to be noticed. 

 Mr. Nowell had ascertained the probable egg capacity of a female to be about 70, and 

 further that the insect can reproduce parthenogenetically. Supposing there were a 

 minimum of 100 females in the cases out of 212 adult insects therein contained (181 

 originally introduced and 31 that hatched out from the cocoons en route), we see that 

 5,000 Phytalus larvae could have been parasitised by them, if we assume an average 

 laying of 50 eggs per female Tijphia. As it was, the cases contained only 530 Phytalus 

 larvae ; many of those that outlived the voyage were non-parasitised, and nearly a 

 hundred Phytalus cocoons were found ; so that it is clear that the egg- laying power 

 of the Tijphia had been considerably reduced under the prevailing conditions. 



As the life-cycle of a Tijphia ranges, according to Mr. Nowell, between 50 and 60 

 days, it is evident that the two larvae found parasitised on arrival had been attacked 

 by wasps of the second generation that emerged during the voyage ; and here again 

 it is a matter of surprise that only two of the Phytalus larvae in the cases were 

 parasitised. 



There is, further, no room for doubt that the reproduction of the Tiphias was 

 continued in the Insectarium up to the fourth generation, with a gradual reduction 

 in the egg-laying power of the females. 



(4) 10th June 1914. — Fourth consignment despatched, and reached Mauritius 

 15th August 1914. This shipment was made under the same conditions, but owing 

 to the scarcity of adult Tiphias the cases were stocked with 29 cocoons and 32 adults 

 only, while Phytalus larvae were placed therein to the number of 1,064. 



Mr. Sydney Dash, Assistant Superintendent of Agriculture, Barbados, was able 

 to ascertain that nearly 15 per cent, of the cocoons had hatched out and that a certain 

 number of Phytalus larvae had already been parasitised before the despatch of the 

 cases. 



One of the cases was received in a soaked condition and from the three others 22 

 male and 10 female Tiphias were obtained. There were numerous non-parasitised 

 larvae, just as in the previous shipment. These cases were left undisturbed, the 

 insects as they emerged being removed and placed in the Insectary so as to allow of 

 the exact number of emergences being known. 



Hatching began on the 4th September and continued up to 24th January 1915, 



when 3 males were found ; 5 females and 10 males hatched out in September, 2 males 



"and 1 female in October, 7 males and 1 female in November, and 3 males in January, 



or a total of 32 insects, which constituted the 3rd generation of the 58 adult insects 



that emerged in May 1914, not taking into account the 4th case that was flooded. 



