605 



action of natural enemies. Bagworms (Ps\'chids) were injurious on 

 two estates, but experiments in spraying were not contimied as natural 

 enemies brought the infestation to an end. 



Oil -palm pests included Oryctes rhinoceros, L. ; the much rarer 

 0. trituberculatus, Lansb. ; Rhynchophoriis ferrugineus, 01. var. 

 schach, F., found in five localities, in two of which the trees had been 

 killed ; Xyleborus sp., which had bored the ribs of the palm leaves 

 and had apparently migrated from infested coffee growing among the 

 palms ; bagworms that in some cases caused entire defoliation ; 

 and caterpillars of Amathusia phidippns, L., DiscopJiora celinde, 

 Stoll, Orthocraspeda trima, Moore, Setora nitens, Wlk., and in the fruit 

 clusters, Meltssoblaptes rtifovenalis, Snell., which is also a pest of 

 coconut. 



Heymons (R.). Mitteilungen uber den Rapsnissler, Ceutorrhynchns 

 assimilis, Payk., und seinen Parasiten, Trichomalus fasciatus, 

 Thorns. [Communications on the Rape Weevil, Centhorrhynchu's 

 assimilis, and its Parasite, T. fasciatus.] — Zeitschr. angew. Ent., 

 Berlin, viii, no. 1, September 1921, pp. 93-111, 10 figs. 



The observations here recorded on Ceuthorrhynchiis assimilis, Payk., 

 which is a serious pest in North Germany, refer to rape unless otherwise 

 stated. This weevil was practically the sole representative of its 

 genus in the fields examined near Berlin, though C. sulcicollis, Gyll., 

 was also seen. 



The adults appear early in the spring, before the rape blossoms. 

 When the investigations began, on 19th April 1920, infestation, 

 averaging two weevils per plant, was already noticeable. They feed 

 on the flower-buds and stalks bj/ night as well as by day, but from 

 an economic standpoint the spring infestation is unimportant. On 

 23rd April mating occurred in the laboratory, and was observed in the 

 field on the 25th. On 14th May oviposition was first observed, the 

 eggs being deposited in a rape pod, in a hole specially bored with the 

 proboscis. Towards the end of the oviposition period the weevils 

 die in increasing numbers, only a few females being seen boring pods 

 in the first fortnight of June. 



The egg is laid near a seed inside the pod, and sometimes within a 

 seed. The egg-stage averages 8-9 days. The first newly hatched 

 larva was found in a rape pod on 19th May. After destroying the 

 ripening seeds in four or five weeks the larva cuts a hole through the 

 pod and drops to the ground, where pupation takes place. After 

 about ten days the young adult breaks its earthen pupal cell and 

 works Its way to the surface. In July and August, after rape had 

 been harvested, considerable numbers of young weevils were seen on 

 the sides of paths, or in fallow fields on wild mustard {Sinapis arvensis). 

 With the advent of cold weather the young weevils seek shelter. It 

 is probable that hibernation occurs in or on the ground. 



These observations show that C. assimilis has only one annual 

 generation, and agree with existing records on allied species. 



The larvae were parasitised by a Pteromalid, Trichomalus fasciatus, 

 Thoms., which does not appear to have been recorded from this 

 weevil. Other species of Ceuthorrhynchus are also probable hosts. 

 The parasites occurred chiefly in May, and though oviposition was not 

 observed, it appears that only one egg is laid on a weevil larva inside 

 a rape pod. All the parasitised larvae were about half-grown. 



