Vol. XII. No. 284. 



THE AGRICULTURAL XEWS. 



'^o 



THE HUMBLE-BEE. By F. W. L. Sladen, F.E.S. 

 Macmillan id Co. Ltd. Price 10«. net. 



The book which bears the above title gives a most 

 interesting account of careful observations in a fascinating 

 nature .study. 



The author has been a student of these insects from the 

 days of his boyhood, and his acquaintance with them is not 

 a casual one but savours throughout the book of a friendly 

 intimacy. As a result, his account of the life history of the 

 species of British humble (or bumble) bees of the genus Bom- 

 bus and the parasites, or perhaps better, the usurpers of the 

 genus Fsithyrus, is a narrative full of interest to the reader and 

 one which conveys to him a sense of the enthusiasm of the 

 naturalist. This portion of the book comprises the first four 

 chapters. 



Humble bees are essentially inhabitants of the north, 

 and they flourish best at about the latitude of Great Britain. 

 They occur abundantly in Europe, central Asia and North 

 America, their range northwards extending to within the 

 Arctic circle. 



They are found in the Himalayas at altitudes from 2,000 

 to over 12,000 feet. They do not occur in the plains of India, 

 nor in Africa except along the north coa.st. and Australia and 

 New Zealand have no native .species. Where they occur in 

 the tropics they are generally confined to the mountains, 

 although Brazil has a few indolent-looking species. 



The number of distinct species of humble-bees is probably 

 something over 100, of which seventeen are recorded as 

 occurring in the British Isles, while the varieties or sub- 

 species amount to over 1,000. 



The humble-bees are social insects living in societies or 

 colonies. The fertile queen survives the winter and in early 

 spring undertakes the forming of her nest. A suitable place 

 having been found, she proceeds to make the necessary 

 preparations for the raising of her family, preparing it for 

 occupancy by forming in the midst of a mass of fine dry 

 grass or moss a small cavity, in the centre of the floor of 

 which she fixes a small lump of pollen moistened with honey; 

 upon this she deposits eggs in a small waxen cell. She 

 broods over these eggs, incubating them with the heat of her 

 body, leaving them only to collect food, part of which is 

 eaten at the time of gathering and a part is stored in 

 a specially constructed waxen lioney jiot as a supply to be 

 drawn on during bad weather when she cannot forage. 



The eggs hatch four days after they are laid; the larvae 

 become full-grown in .seven more days, and they then pupate, 

 and in another eleven or twelve days emerge the first perfect 

 insects of the new brood. During all this lime, twenty-two 

 or twenty-three days in favourable weather, the queen has 

 had to work alone, building the nest, hatching the eggs and 

 collecting food, then keeping the larvae warm and feeding 

 them, and later keeping the pupae warm to hasten their 

 emergence. From this time on she has the a.^sistance of the 

 workers from the first lot of eggs and her function now 

 becomes one of egg- laying almo.st entirely. 



The account of the activities of the nest for the remain- 

 ing week.s of the summer is full of interesting detail, down to 

 the time when on the advent of the cool weather of autuum 

 the mother queen, worn out with the arduous duties of the 

 season, succumbs to fatigue, chill, and the inevitable result of 

 the accomplishment of her life-work. Many queens fall vic- 

 tims to natural enemies and many nests fail to develoj) suc- 

 cessfully. From the prosperous ones, however, are developed 

 males and females ; the latter, after mating, hibernate until 

 the following spring : the males die on the advent of the cold 

 weather. The account of the usurpation of the nest by the female 

 Fsithyrus is also of interest. This in.sect invades the Bombus 

 nest and, after ingratiating herself with the workers, kills 

 the queen which she finds there, and becomes the egg-laying 

 mother of the nest, the Bombus workers rearing the 

 Fsithyrus young, as they normally rear those of their own 

 kind. As a result of this habit, the Fsithyrus bees do not 

 include workers among their castes, the Bombus workers 

 being relied upon to care for their young. 



The Fsithyrus bees and those of the Bombus group are 

 closely related and are probably descended from a common 

 ancestral form. The species of Fsithyrus generally resemble 

 the particular species of Bombus whoso nests they invade. 

 Humble-bees are attacked by many enemies in addition 

 to Fsithyrus. among which perhaps the chief are mice and 

 shrews. Other insects, mites and nematode worms also prey 

 upon or parasitize them. Birds are not serious enemies. 



Turning to the information presented regarding the 

 domestication of the humble-bee, in chapters five to seven 

 there are given accounts of finding and taking nests, descrip- 

 tions of the houses and artificial nests which have been used 

 in the studies of these insects, and an interesting general 

 account of the domestication of humble-bees. 



Chapters eight and nine give an account of the British 

 species of Bombus and Fsithyrus. This portion will be of 

 the greatest interest to students of these insects, for in 

 addition to the descriptions and tables for separating the 

 species, there are five plates reproduced in colour from photo- 

 graphs from nature showing all these insects at natural size, 

 including the males, females and workers of Bombus, and the 

 males and females of l\sithyrus. The colour plates are 

 excellent examples of this kind of photographic reproduction. 

 The bumblebees are useful in connexion with the 

 pollination of many flowers with long corolla tubes, their 

 long tongues making it possible for them to reach the 

 nectaries which the shorter-tongued honey bee and others 

 could not get at, with the result that they would soon cease 

 to visit such flowers The author describes the honey stored 

 by the humble-bees as being of a pleasant taste; American 

 writers, however, do not consider the tast3 of the humble- 

 bee honey of that continent as being at all pleasant. 



In the West Indies the true humble-bees do not occur, 

 or if they do, the occurrence is rare and these insects are not 

 known as familiar objects. Tlie large black carpenter bees 

 of the genus Xylocopa, which are called humble bees, are 

 solitary in habit, and dirt'er in many important points of life- 

 history. In the first sentence of the introduction, Mr. .Sladen 

 says: 'Everybody knows the burly good natured humble-bee.' 

 One can only wish that this were so in the tropics, for whilst 

 the interest of the liook is bound to be felt by the reader, 

 the study of the insects which would naturally accompany 

 the reading would greatly increase the interest 



In addition to the attractive nature of the subject matter, 

 the book itself is worthy of mention. Printeil in large clear 

 type, on good paper, excellently illustrated and well bound 

 in brown cloth, it is worthy of a place on the shelves of every 

 entomologist and lover of nature. 



