4 



No. 47. — A Potato Weevil, 



In June last, Mr. H. McDermot, of Grand Cayman, sent to the Museum specimens of a small 

 weevil, both adults and larvae, with the report that they were injuring potatoes in that island. 



This weevil ia the Cylas formicarius. The adult is about 6 ram. long, of a dark greenish or bluish 

 black, with the head, thorax and legs orange-coloured, the beuk being blackish. The head and thorax 

 are narrowed and elongate, giving the insect an elegant appearance. Tbe small maggot-like grubs of 

 this weevil are wholly of a whitish colour, and are the stage which does the injury to the tubers. 



Mr. MacDermot writes that this weevil has within the last four or five years become generally dis- 

 tributed and extremely troublesome to the cultivation of the Potato. It. attacks potatoes of all kinds, 

 but especially the large white variety, and has apparently been introduced from Cuba or Pedro (St. 

 Elizabeth) where it abounds. Infested potatoes present the appearance outwardly of being sound and 

 good, but on being split open disclose the worms boring in every direction. Immediately next the 

 borings the tissues of the tuber are black and discoloured, while the remaining portions are said to be 

 tasteless, and are often refused even by pigs. 



It appears that the tubers attain a certain size before they are attacked, and are therefore sometimes 

 dug early, before they are large enough to be good eating, so as to escape the worms. Sundy soil and 

 deep planting are said to be preventives to a certain extent of the destructiveness of the worms. 

 Aug. 29th, 1893. 



[ Cylas formicarius is also native to Jamaica, but is an addition to the lists of identified species . 

 — C. H. T. T., Nov. 2, 1893.] 



No. 48.— A Jamaican Bean Weevil. 



In July, Mr. Fawcett sent to the Museum a box of "red peas," Phaseolus nanus, which were in- 

 fested with a weevil. They were received from Mr. W. Grant, of Cave Valley, in St. Ann's, and are what 

 are commonly known in America as "string beans." These beans contained small holes, in which a 

 large number of the weevils had bred, quite the same as those made by the pea and bean weevils in 

 more northern countries. Specimens sent to Dr. Riley in Washington were determined as Bruchus 

 tetricus Gyll. The more destructive weevils of this genus in America are B. pisi and B. ohtectus, which 

 attack peas and beans respectively in that country. There are many other species of this family Bru- 

 chidae, of which the great majority breed in seeds of leguminous plants. Tbe eggs of the pea and bean 

 weevils are deposited in or on the young pods usually, and the newly-hatched grub, as recently des- 

 cribed by Dr. Riley, contrary to the rule among weevil larvae, is furnished with legs. These it soon 

 loses, however, having passed the post-embryonal stage, and becomes a maggot-like larva enclosed in 

 the bean or pea. Briichns tetricus, above mentioned, is new to the Jamaican lists. A species, supposed 

 to be B. rufimanus, was found by Mr. Cockerell in white beans ( Labial vulgaris var. bonavist ) in the 

 Museum of the Institute. He, however, doubted whether they were a Jamaican product. The only other 

 Bruchus recorded from Jamaica is B. spiMos?/s, a rather large spinous species whose habits are not known. 



As a remedy for these weevils in dry beans or peas in bulk, bi-sulphide of carbon is most efi^ectual 

 as it kills every stage of the insect, from egg to adult beetle. A very small quantity — one or two ta- 

 blespoonfuls — should be poured into a barrel, or other tight receptacle containing the beans, the barrel 

 being then closed and left for a few hours. It should afterward be opened and the bi-sulphide allowed 

 to thoroughly evaporate, the building being thrown open, if it is done within doors, and no light or fire 

 should be introduced in the meantime, as the vapours are highly inflammable. 



August 31st, 1893. 



No. 49. — The Cynthia Silk Worm Experiment. 

 The Cynthia silk worm, Attacus cynthia, is a native of China, India along the Himalaya Moun- 

 tains, and Assam. It has been naturalized in the the United States and in France, and ia cultivated 

 somewhat in parts of Africa and in Auatrialia. The larvae are quite easil y reared in the open air 

 in northern countries. 



The native food-plant of this silk worm is the Ailanthus tree, but it ia said that it will also thrive 

 on the castor oil plant, lilac, cherry, barberry, laburnum, and others. 



Last January some coooons oE this species were sent to the Museum by Mr, D. Morris, of Kew, 

 through Mr. Fawcett. They were obtained by Mr. Morris from Mens. A. Wailly, the well known 

 silk worm authority. M. Wailly imported them from the United States, where they had been raised. 

 Eggs obtained from moths which issued from these cocoons were distributed by Mr, Cockerell in 

 March, to seven persons in different parts of the Island. Cocoons were previously sent to four others. 

 The castor oil plant was suggested as the most suitable food for the worms. 



The experiment unfortunately ended disastrously in each case, Ooly one correspondent secured 

 the cocoons from the eggs, and they were valueless. In all other cases the larvae died from one 

 cause or another. It Avas complained that the worms would not eat the castor oil leaves. In some 

 cases, lettuce was eaten in preference. 



Apparently the climate and the food plant are not well adapted to the apecies in Jamaica. Yet 

 it would seem that it might be made to thrive with proper food and care in the more mountainous dis- 

 tricts. It would seem that the other very closely allied species, Attacus ricini, whose native food is the 

 castor oil plant, would be much better adapted to our Island, 



Mr. Cockerell records breeding an American parasite, Spilochalcis mariae, from the Cynthia 

 cocoons. These parasites had survived the pasaage of the cocoons from America to England, and 

 thence to Jamaica, where they issued. 



September 5th, 1893. 



No. 53. — The Pimento Borer, 

 In October, 1892, some pimento sticks were sent to the Museum by Mr, A, E. Husband, of Man- 

 chester. They were infested with longicorn larvae, and were placed by Mr, Cockerell in ajar to breed. 

 The following July, the sticks having remained in the jar undisturbed during the interim, it wa 



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