12 



SCIENTIFIC NEWS. 



[July 6, 1888. 



the apex itself is developed into a very long, curved, 

 almost fang-like claw, reminding one very much of that 

 upon the tail of a scorpion, save and except that it is not 

 perforated for the transmission of poison. The foot is 

 quite small and insignificant, used in walking only, and 

 never employed in the capture of prey. 



These formidable limbs, as already mentioned, are 

 raised high in air while their owner is lying in wait for 

 prey. No sooner does a victim venture within reach, 

 however, than they are thrown sharply forward and 

 downward, and the insect, or whatever it may be, is 

 seized between the thigh and the lower leg, the teeth upon 

 which hold it securely imprisoned notwithstanding its 

 struggles. The legs are then folded closely to the body, 

 chiefly by the action of the coxa, the captive is brought 

 into contact with the jaws, and there it is firmly held 

 while its conqueror leisurely picks it to pieces and 

 devours it. 



The muscular system of these curious weapon-legs is 

 exceedingly powerful, as is amply shown by the mark- 

 edly triangular shape of every joint. And, as the 

 lower part of the leg fits, when the limb is folded, into a 

 groove upon the thigh, and as the teeth closely interlock, 

 it is tolerably evident that a victim, when once seized, 

 can have but very little hope of escape. 



This structure is common to a large number of insects 

 belonging to the group, whose slowness of foot is thus 

 amply compensated for by the formidable character of 

 their natural weapons. And their green colour and leaf- 

 like appearance of course assist them very greatly, by 

 assimilating them to their surroundings, and rendering 

 their detection by their anticipated victims an almost 

 total impossibility. 



Now, in the mantis shrimp, strange to say, although a 

 crustacean and a dweller in the water, we find a struc- 

 ture almost precisely similar in detail as well as in 

 principle. And a most admirable illustration it supplies 

 of the law that identity of habits produces identity of 

 structure, even in creatures not in any way allied to one 

 another, and existing under conditions of a totally 

 different character. 



Again we find the long raptorial fore-legs constituting 

 weapons of offence, and armed, just as in the mantis, 

 with a formidable array of strong and sharp spine-like 

 teeth. Again we find the lower part of the limb fitting 

 into a groove upon the upper, in order that the grip may 

 be the more severe, the possibility that the victim should 

 break away the less. And the chief, in fact the only, 

 difference in the weapons of the two creatures is that in 

 the crustacean the coxa is not prolonged, and that in con- 

 sequence the teeth are set upon the foot ; while it is the 

 foot which is received into a groove upon the lower leg, 

 and not the lower leg into a groove upon the thigh. 



By those who have kept it in captivity, the mantis 

 shrimp is said to use its raptorial limbs with wonderful 

 address. Dr. Lukis, for example, speaking of his own 

 specimen, tells us that " it placed itself in a menacing 

 attitude, which would rather have excited the fear of 

 exposing the hand to it I brought a silver tea- 

 spoon near it, which was struck out of my hand with a 

 suddenness and force comparable to an electric shock. 

 This blow was effected by the large arms, which were 

 closed and projected in an instant with the quickness 

 of lightning." 



In a smaller crustacean, also, popularly known as the 

 Skeleton Screw,and scientifically as Caprella linearis,avery 

 similar structure is found; but its efficiency is still further 



increased by a corresponding modification in the second 

 pair of legs also, so that four raptorial organs are provided 

 in the place of two. No groove is present upon the lower 

 part of the leg, but that joint, which is enormously large, 

 is armed with a double row of long [and sharp teeth, 

 between which the food is received, and which practically 

 answer the same purpose. The foot itself, too, is 

 sharply notched along the edge. And both attitude and 

 action of the creature, when seeking for prey, are so 

 singularly suggestive of those of the mantis, that it is 

 quite difficult to realise that the two have absolutely 

 nothing in common with one another. 



Instances such as these are not uncommon, although 

 seldom do we find the resemblance so complete in 

 creatures so widely different. And yet, since the resem- 

 blance does exist, it is somewhat singular that the 

 peculiar structure in question is not more common, seeing 

 how great is the number of predacious beings, and how 

 many of them, so far as we can tell, would benefit by the 

 possession of raptorial limbs. Something similar we see 

 in the water scorpion, the water gnat, and the stick- 

 like Ranatra linearis, all of which capture their prey by 

 the aid of modified fore limbs. But in none of these 

 do we find the true mantis structure, which is so very 

 pronounced in the creatures described. And we thus 

 have a double and seemingly paradoxical source of 

 wonder ; firstly, that the similarity should exist at all, 

 secondly, seeing that it does exist, that it is not far more 

 common. 



The Poison of Bees. — According to some investiga- 

 tions which Professor Carlet, of the Faculty of Sciences of 

 Poitiers, has recently communicated to the Academy of 

 Sciences at Paris, the poison-apparatus of bees comprises 

 two quite distinct sets of glands, some yielding an alkaline 

 secretion and others an acid product. For the full effi- 

 ciency of the venom a mixture of the two liquids is re- 

 quired. The alkaline glands, which are highly developed 

 in the bees and in all other Hymenoptera with a barbed 

 sting, are merely rudimentary in insects of the same 

 orders which use their stings not for defence against their 

 enemies, but for paralysing a victim destined for the food 

 of their larvae. (If a bee is caused to sting into a piece 

 of blue litmus paper, a red spot is produced, showing that 

 the acid is in excess. The sting of a wasp, on the con- 

 trary, as it was first pointed out by Professor Church, and 

 as we have since confirmed, has an alkaline reaction. It 

 is very probable that all the animal venoms are of a com- 

 plex nature. There is here evidently room for further 

 research, which we recommend to persons in districts 

 where the hornet is plentiful. — Ed., Scientific News.) 



Application of Sulphate of Copper to Fruit Trees. 

 — M. Magny, President of the Horticultural Society of 

 Coutance, writes to the National Horticultural Society of 

 France as follows: — " Every year, about the months of 

 February and March, when the fruit-buds on fruit-trees, 

 of whatever species, begin to swell, birds (and especially 

 bullfinches and tomtits) fall upon the fruit-trees and pick 

 the buds to such an extent as greatly to compromise the 

 hoped-for crop. Having in vain tried various methods, 

 I had the idea last year of entirely covering my trees, 

 especially the fruit-bearing branches, with the following 

 composition : — 4 lbs. of lime slaked in 6 pints of water, 

 1 lb. sulphate of copper (blue stone); dissolve in 67 pints 

 of hot water, add then 1 lb. of soot and clay enough to 



