The Planters' Insect Friends. 37 



through, fertilisation taking place at once at'ier emergence after some 

 struggle among the males. The females were thus at once prepared for 

 the deposition of fertile eggs." 



I have observed the life-history of the yellow parasite from egg- 

 laving to adult. I was enabled to do so in the following way. On the 

 afternoon of Friday, August 30th gone, I was in a caneheld of an East 

 Toast estate searching for freshly laid egg-clusters of Diatrcea. Shortly 

 alter securing one and while I had it in my hand on a bit of the blade on 

 which it had been deposited, one of the yellow parasites alighted on it 

 and began to parasitize it. So engrossed was the tiny creature in its 

 task, that it kept to it even though I continued moving along on the 

 hunt for more clusters. Now and then I paused to note under a hand 

 lens the method of parasitization. It began its work at 3 p.m., and 

 about 4.30 p.m., by . which time I had travelled back by batteau to the 

 factory yard, it seemed to have finished. During the hour and a half it 

 walked off from the cluster three or four times but returned again each 

 time to resume thrusting its ovipositor into the eggs. It seemed that it 

 desired to make sure it had dealt thoroughly with each of the thirteen 

 eggs composing the cluster. 



By Sunday, September 1st, several granular objects — -the developing 

 parasites — could be seen in the eggs, which had then begun to show 

 very faint orange traces. By the next morning the cluster was beginning 

 to blacken, and by Tuesday it was quite black. By Wednesday of the 

 following week the parasites had emerged, thus giving about 12 days 

 from egg-laying to adult. On another occasion on a West Coast estate 

 I came upon a parasite at rest on an egg-cluster. I brought it from the 

 field, and carried it on a railway journey of 11 miles to the ferry wharf. 

 While waiting for the ferry steamer darkness began to come on, and it 

 was only then that the parasite became restless, and flew away to seek 

 shelter for the night I supposed. The parasites are so tiny and frail, 

 and must often have to search so long and hard for fresh e^g-clusters 

 that it is not to be wondered at that when they discover one they 

 become oblivious of everything save the immediate businesss in hand, 

 viz., that of parasitizing the eggs in order to continue their own species. 

 Neither of these parasites has been identified by a specialist, but the 

 yellow one is probably Trichogramma ■pretiosa which is found in the 

 West Indies. 



Although the yellow one is oftener met with, instances may be 

 observed where eggs over entire fields have been parasitized almost 

 exclusively by the black one. 



Another important parasite of Diatrcea is a Braconid corresponding 

 to one in the local museum named Tphiaulax medianus by Cameron. 

 It is red with wings fuscous, but nearly hyaline towards the base, and 

 with stigma yellow- or ochraceous. It parasitizes the caterpillars singly, 

 and is at ceitain times plentiful in severely infested fields. The adult 

 female parasite on alighting upon a cane, searches for a Diatrcea boring, 



