322 Journal of Agrictiltural Research v.4111. no. 4 



Hawaiian limes possess less rag than sour oranges and the larvas reach the 

 pulp more easily. In 1,692 ripe and yellow limes picked during April, 

 showing an average of about 5 punctures to the fruit, the larvae succeeded 

 in reaching the pulp in but 287 cases. Chinese oranges have been shown 

 to be generally infested because they possess a very thin, loosely fitting 

 rind, and for practical purposes may be said to possess no rag. Unfor- 

 tunately the writers have had but little experience with tangerines (Citrus 

 nobilis), as these are rarely found in Hawaii, but such few fruits as have 

 come to their attention have been well infested, which is to be expected, 

 because of their thin, loosely fitting rind and rag. 



PERSISTENT ATTACK LEADING TO INFESTATION OF THE PULP 



Laboratory experiments and field examinations have shown that the 

 female fly seldom deposits more than six eggs in a puncture at one time. 

 So well has nature equipped the average citrous fruit to withstand attack 

 that it is doubtful whether such fruits as the grapefruit, lemon, or orange 

 would ever become infested ' until very much overripe, if the female fly 

 fonned a new puncture for each batch of eggs deposited, thus making it 

 necessary for the lar\'£e hatching from each lot of eggs to face identical 

 difficulties in reaching the pulp. This, however, she does not always do. 

 As many as 153 eggs have been taken from a single puncture in grapefruit. 

 A very large number of punctures contained more eggs than the female 

 deposits normally at one oviposition. It is very evident, therefore, that 

 females o\'iposit in a large number of instances in the same puncture 

 rather than make a fresh puncture for each batch of eggs. Frequently 

 freshly laid eggs have been found in egg cavities from which channels 

 made by larvae from pre-viously deposited batches of eggs extend through, 

 to, and into the pulp or in punctured areas of the rind showing dry decay 

 which is known from observation to have been forming for fully one 

 month. Usually the rag beneath a puncture develops a discolored area, 

 no matter whether the puncture originally contained eggs or not, and 

 very often this discoloration of the rag, which appears to be caused by a 

 dry rot, extends to the outer rind and causes deadened, sunken areas to 

 fonn about the punctures. Such blackened areas, which had been 

 developing in the rind of well-punctured oranges held at the laboratory 

 for one month after picking, arc shown in Plate XLII, figure 2. 



It has already been stated that many larvae die in the rag and that 

 before dying some of these lar\-K channel through the rag in all directions. 

 Often all the larvae escaping from a puncture will be found dead next the 

 skin protecting the pulp; again they will be found dead at the heads of 

 channels extending fully i inch from the puncture. In large shaddocks 

 they may even channel 3 or 4 inches through the loose rag (PI. XLI). 



I The term "infested" is here applied to fruits which have larvse in the pulp, show decay, and become 

 generally tmfit for consumption. 



