40 BULLETIN 647, U. S. DEPARTMENT OF AGRICULTURE. 



these examinations it was found that from as low as 0.7 per cent to 

 as high as 54 per cent of the ants which had any kind of forage car- 

 ried white flies. Other of the lower percentages were 0.9 per cent, 

 3.1 per cent, 3.2 per cent, and 13.8 per cent; while other higher per- 

 centages were 21 per cent, 21.7 per cent, 34.7 per cent, and 38.4 per 

 cent. Most of these examinations were made at times when the 

 foraging was not too heavy, so that the ants could be counted without 

 danger of confusion, and the number of ants carrying white flies 

 was often too large to count. The percentage of ants with forage in 

 their possession in these examinations ranged from 16.1 per cent to 

 75.8 per cent. 



The above phenomena, which were observed many times on citrus 

 and other plants every season spent in Louisiana, always may be 

 seen during the emergence periods of the white flies in orange groves 

 invaded by the ant. At times the ants with their captives are so 

 numerous that the most casual glance will discover them as they go 

 wavering down the trunks with the white-fly wings spread above 

 their heads like diminutive sails. At times, when such a caravan is 

 suddenly struck by a light breeze, the little sails will scatter in every 

 direction as the ants hunt for temporary shelter to prevent being 

 blown out of their course. The only possible direct part played by 

 the ant in its relations with the adult citrus white fly in Louisiana 

 is that of predacious enemy. 



Relations of the Ant with Immature Stages of the White Fly. 



Investigation of the behavior of the ants toward larva? and pupae 

 of the citrus white fly brought out the fact that, although they hover 

 about these immature stages more or less, they do not palpate the 

 larvae or directly obtain their excretion, but that they watch over 

 the pupa? solely for the purpose of capturing the emerging adult 

 insects. Although the ants do not capture living white-fly larvae, and 

 only a comparative!}* few pupae, they are occasionally seen carrying 

 the latter. Th"; pupae taken are nearly always those in which the 

 transformation to the adult is almost completed, the ants becoming 

 impatient at waiting for the adult to appear or being impelled to 

 attack by its attempts to extricate itself from the puparium. In 

 some instances as many as 8.7 per cent of the white flies taken from 

 the ants have been pupae, but this proportion is doubtless above the 

 average. 



When most of the white flies on a heavily infested tree overrun 

 with ants are in the larva stage the ants never are found in attend- 

 ance in considerable numbers on the worst infested leaves. The ants 

 have been seen to lick the leaf surface in the vicinity of white-fly 

 larvae and they undoubtedly secure a certain amount of white-fly 



