392 



Dry (F. W.). Notes on the Coconut Beetle {Orycies monoceros, 01.) 

 in Kenya Colony. — Bull. Ent. Rei.., London-, xiii, pt. 1, May 

 1922, pp. 103-107. 



This is a brief account of work of a preliminary nature carried out 

 on the East African coast mostly between August 1920 and February 

 1921. Of thirty records the average duration of the egg-stage of 

 Oryctcs monoceros, 01., was 15 days, with a minimum of 12 and a 

 maximum of 20 daj's. The beetles do not lay eggs readily in captivity. 

 They were kept in two-pounci biscuit tins about one-third filled with 

 powdered material from the inside of decaying coconut logs, in w'hich 

 the eggs are mostly laid in the field. In captivity they fed readily 

 on the husk of unripe coconuts and bits of sugar-cane ; in the field 

 they feed on the young fronds at the top of the palm. Although a 

 number of females lived more than a hundred days, the largest 

 number of eggs obtained from one individual was 30, but i t is thought 

 that a greater number are laid under field conditions. Owing to the 

 high mortality great difficulty was experienced in rearing the larvae. 

 The average duration of the larval stage was probably 100 days, 

 the shortest being 82. The extremes of the pupal period were 19 

 and 28 days, with an average of 21. Cocoons were apparently only 

 constructed when the insects were confined in fibrous material : 

 in the field pupation occurs just below the material in which the grubs 

 have fed. About four and a half months elapse between oviposition 

 and the emergence of the adult. Logs exposed to weather conditions 

 may very quickly become breeding grounds for the beetles. 



The usual methods of control are the destruction of these logs 

 and the collection of the beetles. From a plantation of about 1,250 

 acres, containing approximately 50,000 trees, 13,072 beetles were 

 collected in three years ; of these 7,100 were collected in 1918, 

 whereas in '1920 the numbers were reduced to 632. Similar counts 

 have also been made on other plantations. All stages of the insect 

 may be found at any time. The mortality due to overcrowding in 

 the breeding- places is probably a factor exercising " facultative 

 control." 



From a comparison of the extent of beetle damage in areas where 

 the concUtions affecting the insect were strikingly different, it appears 

 that old trees are attacked more than young ones. If native plantations 

 remote from thick bush were kept free from breeding-places, they 

 would suffer comparatively little attack. In the bush surrounding a 

 European plantation eggs and larvae were obtained from dead logs, 

 chiefly dead mukoma palms, but in this material other beetle grubs 

 were much more plentiful, and they were living in much harder material 

 than any in which 0. monoceros was found. From these grubs a 

 Cetoniid, Pachnoda euparypha, Gerst., has been reared. There are 

 large areas of similar l)ush along the coast belt, and the relation of 

 0. monoceros to it needs investigating. The present observations 

 suggest that though it is a source of beetles, it may not provide a 

 favourable l)reeding groinid for them. 



Theobald (F. V.). An Aphid Genus and Species new to Britain 



{Trilohaphis caricis). — /:///. Mtldy. Mag., London, Win, no 697, 

 3rd Ser. viii, no. 90, June 1922, pp. 137-138, 2 figs. 



The viviparous female of Trilobaphis caricis, gen. et sp. n., is 

 described from ^^^ales, where it was taken on Carex remota. 



