52 



by wind. By treating the coffee-plants before they wilt, it is found 

 that the stems very rarely show emergence holes, and generally contain 

 only larvae that require another month's development when placed 

 in cages before transforming to adults. After emergence, mating 

 and o\'iposition occur rapidly, sometimes on the same day. 1 he 

 adults take no food, although they may live three weeks or a month 

 if the weather is sufficiently cold to keep them inactive ; normally, 

 adult life lasts a fortnight or less. 



Eggs are deposited on the main stems ^\^th much care and after 

 much deliberation on the part of the female, in such a manner as to 

 offer every advantage to the larva for penetrating the stem and at 

 the same time of protection from ants or other enemies. The number 

 of eggs deposited by one female varies greatly and is difficult to 

 determine, but it seems probable that one individual under normal 

 conditions may lay from 50 to 80 eggs, only one or two being deposited 

 in one place, and several plants being commonly attacked. The 

 eggs are soft and adapt themselves to the cavities into which they are 

 thrust. The larva upon hatching penetrates the stem, leaving behind 

 the egg covering, which serves to indicate the entrance hole, and begins 

 to construct a gallery, generally at first almost perpendicular to the 

 surface of the stem, then running under the bark and gradually turning 

 to the interior. As the larva nears maturity, the gallery frequently 

 almost girdles the stem, so that it readily breaks off at that point. 

 Before pupating, a cell is constructed near the bark, in which trans- 

 formation takes place. The larval stage is very variable, even in 

 individuals from eggs laid on the same day, lasting from 3 to 6 or 7 

 months. Being completely protected in their galleries, the larvae 

 cannot be destroyed by enemies, and in fact no parasitism, either by 

 insects or fungi, has ever been noticed in this species. The larvae are 

 very robust, and poison applied to the stems does not seem to deter 

 them from entering, or, in fact, to have any effect upon them. The 

 only possible methods of control therefore are the suppression and 

 destruction of infested plants and the prevention, if possible, of 

 oviposition. The larvae when mature cease feeding and remain 

 inactive for about eight days. The pupal stage, passed within the 

 pupal cell, is generally from 2 to 3 days, sometimes longer in winter. 



In considering remedial measures it must be borne in mind that 

 these must be inexpensive, in view of the numbers of trees to be dealt 

 with, and easy of application, since only native labour is available. 

 It is advisable to avoid the vicinity of forests or heavy undergrowth 

 in choosing a site for a coft'ee plantation, and a new plantation should 

 not be started in the neighbourhood of an old one that is already 

 infested. It is necessary to watch the plantation almost all the year 

 round and cut out infested plants as early as possible, before they 

 have begun to decay. The signs of borer attack are described. The 

 first indication is generally a yellowing of the leaves ; the blossoming 

 of infested plants is frequently abundant and sudden, although the 

 plants appear no more vigorous than their neighbours, and berries in 

 all stages of ripeness may appear simultaneously on one tree. Some- 

 times small branches, generally at the head of the tree, may die oif. 

 It is a serious sign when termites are found on the plants, for these 

 profit by the old emergence holes and galleries of the borer to enter 

 and attack the wood. In this case there is frequently a visible 



