446 



NATURE 



[August 7, 19 19 



Queens, workers, and males alike are caught by 

 the chaffinch, which usually, with a peck from its 

 beak, first destroys the tail, dropping the latter to the 

 ground, eats out the contents of the abdomen, then 

 breaks into the thorax, and finally drops the hollow 

 remains of the insect to the ground. 



In 1912 young birds of a late brood accompanied 

 their parents to two trees in Hertfordshire, but 

 showed fear of the bees, and would eat them only 

 when caught and offered by their parents. 



The blue tit is said to treat hive-bees in much the 

 same manner (Cheshire, "Bees and Bee-keeping," 

 vol. ii., pp. 578-79, 1886). 



The shrike, or "butcher-bird," pierces queen 

 humble-bees through the side of the thorax, after 

 catching them on the wing in its beak, apparently 

 with the view of causing general paralysis before 

 impalation upon the thorn during formation of the 

 "larder." 



Toads are known to feed voraciously upon hive-bees, 

 swallowing them whole, and it is at present very 

 doubtful if any of the birds mentioned are affected 

 by the stings of bees ; but the method of avoidance of 

 being stung cannot be completely overlooked in the 

 cases described for birds. 



The cuckoo is especially addicted to feeding upon 

 caterpillars provided with irritant hairs, and with this 

 we have a rough series showing the downfall of dis- 

 tasteful qualities or defensive weapons in face of 

 selective adaptation in enemies, which for generations 

 must have been kept at bay by such protection in their 

 would-be victims. 



The currant-moth larva, then, has merely been 

 eaten by the thrush, and possibly by the other birds 

 mentioned by Dr. Collinge (save for the cuckoo, which 

 is now adapted to eating distastful insects), when the 

 stress of having to feed a family has made such a 

 practice a necessity. In the case of the song-thrush 

 and its young, the stress has disappeared after a 

 period of seven days with the arrival on the scene 

 of more palatable food. 



The presence of parasites in the caterpillars left 

 after this period can scarcely be more than a co- 

 incidence, and there is no proof that the caterpillars 

 which the thrushes ate were not also parasitised. 

 This explanation would seem more acceptable than 

 Dr. Collinge's paradox based on the assumption that 

 the larvae of the currant moth are not unpalatable to 

 the majority of birds in ordinarv times. 



Edward R. Speyf.r. 



New College, Oxford, July 29. 



Luminous Worms. 



The paper by Dr. Gilchrist published in the Trans- 

 actions of the Royal Society of South Africa, and 

 referred to in Nature of July 31, p. 433, should be of 

 service in reviving interest in this country in the 

 question : Do our indigenous Oligochaets display 

 luminosity? So long ago as 1893 I directed attention 

 to the subject in these columns (Nature, vol. xlvii., 

 p. 462), and in more recent years I have endeavoured 

 to elicit information of a trustworthy nature on the 

 question with but little success. The following worms 

 which have been reported as exhibiting luminosity are 

 common in this country : — Brandling {Allolohophora 

 (Eisenia) foetida), Enchytraeus albidus, and Henlea 

 nasuta. Microscolex ■phosphor eus or an allv is an 

 importation Another worm, which is large, common, 

 and easily observed, is Octolasium. It has a steel- 

 blue body, clay-coloured girdle, and yellow tail filled 

 with fat cells which are often attended by gregarines. 

 Various questions await solution. Of what service, 

 for instance, can luminosity be to creatures which 



NO. 2597, VOL. 103] 



have no eyes? Helodrilus oculatus is the only Lum- 

 bricid found in England possessing organs of vision, 

 and these are rudimentary. They have been reported 

 by Eisen as occurring in Sparganophilus also, twa 

 species of which, as I recently showed, occur in this 

 country. Is it possible that light can influence 

 Annelids in some way, and so facilitate sexual pro- 

 cesses? It was affirmed by Flaugergues in 1771 that 

 luminosity disappears in certain cases after copula- 

 tion, and if that observation is trustworthy it is most 

 suggestive. Dr. Gilchrist, in his paper on luminosity 

 referred to above, suggests that luminosity is a pro- 

 tective device so far as South African worms are con- 

 cerned, and his argument is very plausible. I believe 

 that the yellow extremities of Octolasium serve the 

 purpose of dazzling underground foes by emitting 

 light. 



The reports made years ago to the British Associa- 

 tion of luminous worms found in' Liverpool and in 

 the bogs of Ireland have never led to any satisfactory 

 issue. As I am now writing my monograph of British 

 Oligochaets for the Ray Society, it would greatly 

 interest and help me to receive living specimens of 

 worms which betray phosphorescent properties, or any 

 well-authenticated facts relating to the subject which 

 could be used for purposes of publication or investiga- 

 tion. Hilderic Friend. 



"Cathay," Solihull, July 21. 



Protective Coloration of Birds and Eggs. 



While collecting information on the use of colour- 

 protection among birds, my attention has been directed 

 to what appears to be a very interesting generalisation, 

 viz. that among birds which nest on the moors, sea- 

 shores, and similar open places, (i) those which have 

 the habit of remaining on their nests when danger 

 threatens generally wear camouflaged uniforms, but 

 their eggs seldom show any signs of colour-protection ; 

 while (2) those which are very shy and leave their 

 eggs readily are generally conspicuously coloured, but 

 their eggs are usually camouflaged. 



Amongst the first class are capercailzie, nightjar, 

 partridge, wild duck, and bittern ; and amongst the 

 shy ones with camouflaged eggs are lapwing, curlew, 

 oyster-catcher, terns, ringed plover, and golden plover. 



I do not remember to have seen this point men- 

 tioned explicitly in any book or paper, and should 

 be greatly obliged to any reader of Nature interested 

 in birds who would give me any further information 

 on the subject. Geo. Grace. 



The Museum, Keighley. 



Teeth of Sea-Otter. 



It is commonly stated 'that the sea-otter {Latax lutris) 

 differs from other carnivora in having only two incisor 

 teeth in the lower jaw. Through the kindness of an 

 old Etonian, Mr. Ernest Edwards, our school museum 

 has become possessed of a fine stuffed head of this 

 animal. I was surprised, however, to note that this 

 specimen has three incisors on both sides. In the 

 books of reference to which I have access I can find 

 no such case recorded, and I shall be grateful if any 

 of vour readers can give me information on the point. 



M. D. Hill. 



Eton College, Windsor, July 29. 



The Late Sir Edward Stirh'ng. 



Jn Nature of April 3, p. 87, the late Sir Edward 

 Stirling is referred to as director of the South Aus- 

 tralian Museum. Sir Edward resigned from the direc- 

 torate in 1913, and was succeeded by Mr. Edgar R. 



