Dec. 2, 1920.] Agricultural Gazette of N.S.W. 



869 



banana bulb, were all alive five months later notwithstanding that the winter 

 had been abnormally cold and prolonged. Under natural conditions, there- 

 fore, life must be of considerable duration. 



Although the beetle has wings (Plate II, Fig 1) apparently ample, its 

 capacity for flight has not been definitely established. Some writers assert 

 that the beetle flies, but they do so without authentic confirmation. Some 

 importance must be attached to this point, for if the beetle can fly the value 

 of quarantining plantations as a preventive against the spread of the beetle 

 would be lessened, as infection would then be carried from one plantation 

 to another by direct flight of the beetles. Observations and tests I have 

 carried out, however, while not as yet conclusive, undoubtedly indicate that 

 the beetle does not fly, and infection must be due either to the beetle 

 crawling from one place to another, or, more generally, to the planting of 

 infested suckers. Not only do the wings appear to have lost the power 

 necessary for flight, but I have carefully observed the beetle crawling at 

 night without noting any attempt to fly or even to extend the elytra, as 

 would be expected if the insect could fly. Nor can they under any circum- 

 stances be induced to fly. 



. In the Tweed River district infestation, in almost every case, was directly 

 traceable to the planting of infested suckers. If the beetles fly, healthy 

 plantations adjoining infested ones would, it seems likely, become spora- 

 dically infested. But this does not occur. In only one instance did I 

 find an adjoining plantation infested, and this in two rows immediately 

 contiguous to the most heavily infested section of the infested plantation, 

 indicating that the beetles had crawled over to the clean plantation. Even 

 if the beetle can fly, its habits suggest that the power of flight is rarely 

 if ever utilised, and that it does not move far from the place where it is 

 developed so long as suitable food is available for the egg-laying female. 



Normally the eggs are deposited singly in cavities that the female pre- 

 pares for them with the aid of the mandibles located at the tip of the beak 

 or rostrum, not^vithstanding the fact that some eggs may be dropped 

 loosely on the ground close to the bulb, or among the sheathing bases of 

 the leaves. The locality mostly favoured for the deposition of the eggs is 

 between the leaf-sheath scars on the crown of the bulb just above the 

 ground (Plate II, Fig. 9). Many eggs, however, were also found deposited 

 throughout infested bulbs, the egg cavities being excavated through the 

 sides of the larval tunnels (Plate II, Fig. 8). In captivity, also, the beetles 

 laid freely in the cut surfaces of portions of banana bulbs placed in the cages 

 as shelters for them, notwithstanding that banana suckers were provided 

 for the purpose as nearly as possible to natural conditions. The number 

 of eggs laid by a single female has not been determined, but it seems that 

 the beetles breed continuously and that there is no marked division into 

 definite egg-laying periods. 



On hatching the young larva measures nearly 2 mm. in length, and 

 resembles the mature larva except that it is paler in colour and without the 

 pronounced thickening of the fourth and fifth segments. It immediately 

 tunnels downwards into the bulb, the cavity prepared by the female for the 



