FAMILY BOSTRYCHIDAE 



163 



insect a careful collection should be made of the infested parts, which 

 should be burnt. 



A number of the parasitic and predaceous foes of this Sinoxylon and its 



companion S. analc have been discovered, and some- 



Predaceous Foes. ^^^"^' °^ ^^^^^ ^^^^ histories worked out. Histeridae, 



Trogositidae, and Colydiidae are most commonly found 



as companions and predators of these borers, 



Bracon sp. — In a billet of sissu wood badly infested by S. crassum at 

 Changa Manga I found two Bracon cocoons in the pupating-chambers 

 of the Sinoxylon grubs, as shown in fig. 106. This was on 20 May. The 

 cocoons are papery in structure, elongate, with truncate ends. One was 



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Fig. 106. — Cocoons of Bracon sp. in the tunnels of Sinoxylon 

 crass7im in sissu wood. (The drawing is diagrammatic, the tunnels being 

 shortened.) Changa Manga. (E. P. S.) 



empty, the tiy having tlown. The other had a hole eaten at one end, through 

 which protruded the head and thorax of a small, delicate yellowish Ichneu- 

 mon fly. This fly appeared to be in the act of leaving the pupal case, to 

 crawl up the tunnels of the grub and beetle to escape from the tree. It had, 

 however, died from some cause or other. 



The determination of this parasitic fly has not proved possible. Its 

 grub is undoubtedly parasitic on the Sinoxylon larva. 



Bracon sp. — Some mature flies of a species of Bracon 

 at present undescribed were obtained from a Terminalia 

 tomentosa post from Seoni, in the Central Provinces, which 

 was badly infested by S. crassum. 



Fly. — The mature fly is yellowish brown in colour, wiih long, slender 

 antennae, the characteristic wing-venation of the IJracon flies, and is 

 2.5 mm. in length. Fig. 107. 



These flies were found issuing from the log by the ^"^ Seoni. "^ ' 

 holes of the 5. crassum beetle, and matured at the same 

 time as the beetle. It is probable that their grubs feed parasiticalh- on 

 the 5. crassum grubs. 



Amongst the predaceous insects which attack Sinoxylon crassum, 

 several species of the family Histeridae are known to prey upon the 

 beetle-borer. 



L 2 



