50 



three times, the larvae spun cocoons in the corner of the breeding-cage, 

 whence the adults emerged, the total life-cycle averaging 9 to 10 

 weeks. 



Clainpanain (J.). Notes sur certains Col6opteres xylophages d'Egypte 



at leur Abondance a certaines Epoques. [Notes on certain Xylo- 



phagous Coleoptera of Eg}^t and their Abundance in certain 



Seasons.]— Bull Soc. Entom. Egypt, Cairo, x, no. 2, April-June 



1917, pp. 72-77. [Eeceived 3rd December 1917.] 



In this paper the author records several species of xylophagous 



beetles that increase with great rapidity in Egypt and Syria and do a 



good deal of damage before they can be controlled. An example of 



this is found in the Buprestid, Ptosima undecimmaculat-a,, which is of 



recent introduction and hitherto considered rare in Egypt. In a 



neglected orchard at Matarieh several individuals were found in 



February on a flowering apricot-tree and two weeks later large numbers 



were attacking the same orchard, many of the young trees being killed 



by them. Scolytiis {Eccoptogaster) mulfistriatus hastens the death of 



trees thus attacked. Another Buprestid, Psiloptera catenulata, attacked 



pomegranate-trees in the same orchard, these being further injured 



by the larvae of the Cossid, Zeuzera p)ijri7ia. The Cerambycid, 



Macrotonia palmata, has recently been increasing raf)idly, the larvae 



being found in the trunks of dead and dying apricot-trees. Another 



species, Xystrocera glohosa, which has caused the disappearance of 



Acacia lebbek from the streets of Cairo, would in all probability adapt 



itself to fresh host-plants if this tree disappeared completely from 



Egypt. 



The control of wood-boring insects is difficult ; in the case of a 

 living tree, it is impossible to kill the larvae wdthout causing the death 

 of the tree, and even when a tree is destroyed, the insects continue to 

 develop, although more slowly. In Syria, in the autumn of 1912, two 

 or three individuals of a Bostychid beetle, Apate monacha, were 

 captured and in the following year a swarm occurred, resulting in a 

 heavy infestation of Zinzelats. These insects when placed iu an 

 empty bottle were found to be cannibalistic. They attack for 

 preference old or sickly trees ; vigorous trees, as well as Bauhima 

 variega.ta and Acacia atrox, are defended from the attacks of these 

 beetles by their gummy exudations. 



It is suggested that imported trees that are incompletely acclima- 

 tised, or young and weakly trees are less able to offer resistance and 

 are therefore selected by indigenous or imported wood-boring insects, 

 which adapt themselves easily to new conditions of life and are not 

 highly selective in their choice of food-plants. Indigenous trees are 

 better able to resist attack ; it took some 30 years for Xystrocera to 

 threaten the existence of lebbek trees in Egypt ; Acacia nilotica is 

 still thriving in spite of numerous enemies, such as Lasiocampa, which 

 devours the leaves, Buprestids, Macrotoma and Cossus larvae that 

 devour the wood or live under the bark. A single tree that furnished 

 the author 10 years ago with hundreds of larvae of Cossus is still living. 

 As many new varieties of trees are being introduced into Egypt, it 

 will be necessary to guard carefully against the introduction of new 

 insect enemies, more particularly of those that experience has shown 

 to be capable of adapting themselves to new conditions of life. 



