136 



of attack varies locally very considerably from year to year ; there 

 is a tendency for attacked trees to occur in groups, but tbe position 

 and composition of the groups varies from year to year ; all the 

 trees comprising the final crop of a teak plantation will be bee-holed, 

 while the number of holes in the bole length will be sufficient to render 

 it useless for timber ; mixed forests rich in teak show an appreciably 

 lower borer incidence than pure teak plantations in the same locality ; 

 plantations in which bamboos and trees other than teak have en- 

 croached or infiltrated, so as to form part of the canopy, show a lower 

 incidence than plantations with a dense undergrowth of bamboos 

 and shrubs but with complete caDopy ; the protective effect of under- 

 growth on individual trees is not measurable ; in plantations without 

 any undergrowth the borer appears earlier than in plantations with 

 undergrowth, i.e., as soon as there are trees of 12 inches girth ; no 

 natural conditions of undergrowth or second storey growth offer 

 sufficient protection to the teak crop to cause a requisite reduction 

 in the incidence ; if the trees marked in thinnings are felled before 

 the end of the year the borers in those trees will die ; if thinnings 

 are made in the canopy only, leaving dominated and suppressed trees 

 standing, less than half the number of borers is removed ; the shorter 

 the intervals at which thinnings are made, and the earlier they are 

 begun, the greater the effect on the incidence of the borer, since the 

 percentage of borers removed in thinnings decreases with the age 

 of the crop. 



Ferris {G. F.). A Remarkable Case of Longevity in Insects (Hem., 

 Hom.) — Entom. News, PJiiladelphia, xxx, no. 1, Janiiarv 1919, 

 pp. 27-28. 



The Coccid genus Margarodes contains certain species in which 

 the first-stage larva possesses legs and antennae, these appendages 

 beinj? lost in the intermediate stages and reappearing in the adult. 

 All of the described species are subterranean in habitat, and in all 

 the intermediate stages are enclosed within a tough, hard cyst formed 

 from the secretions of certain dermal glands. 



One species, M. vitium, is a native of Chile and Venezuela, where 

 it feeds upon the roots of grapes, being at times a pest of some 

 importance. It has been recorded that adults have emerged from cysts 

 that have been kept for 7 years upon their being immersed in water, 

 no food having been taken in the meantime. This is apparently an 

 adaption to the peculiar climate of its habitat, where rains occm- 

 but once in 7 years or longer. An instance is here recorded of a speci- 

 men received in 1899 or perhaps earlier, the date of collection being 

 unknown, which, when histologically examined in 1917, gave every 

 evidence of having been alive at the time of fixation, showing that 

 the insect had existed for at least 17 years without food. 



ENTOMOLOGICAL NOTICES. 



Mr. G. F. Hill has been appointed Entomologist at the Australian 

 Institute of. Tropical Medicine, Townsville, North Queensland. 



