Oct. lo, 1872J 



NA TURE 



485 



The development of the grab is carefully described by the 

 author, and a "pseudo-nymph" stage is recognised intervening 

 between the nymph and the pupa. The perfect insect bites off 

 the lid of its cell, and comes out with perfect wings, deposits 

 first of all a drop of urinary excretion, and makes a trial fl'ght, 

 tlien returns to take part in the labours of the colony. The cell 

 is often used again for another egg. Tlie first drones make their 

 appearance with the beginning of Jul-/, an important fact for 

 Siebold's experiments, for if the nest is to be used at all now is 

 the latest moment ; they have to be killed off, and all the remain- 

 ing larvx and pupx destroyed — in order to secure a colony con- 

 sisting solely of virgins. The drones play a pitiable part in the 

 nest — sneaking about in the empty cells and behind the comb, 

 not till the month of August are their generative organs fully 

 developed, and then they make tlieir first approaches to the fe- 

 males. Their proceedings are minutely described, and it appears 

 that they meet with many rebuffs from the busily-occupied 

 workers of the hive, and that it is outside at a distance from the 

 nest that tlieir addresses are at length accepted by those of the 

 larger females destined to become queens. Not all the large fe- 

 males appear to have this destiny, and none appear to leave the 

 nest until all the brood has been brought through, when (about the 

 beginning of October) the nests become deserted. Only a few 

 flattened old virgin wasps remain, who are killed off by the 

 frosts, whilst the young queens have married and sought out 

 for themselves winter quarters. Siebold distinguished black- 

 eyed and green-eyed drones, and speculates upon tiie signification 

 of this difference. 



Having ascertained these and other matters relating to the 

 Tolistes in far greater detail than we have been able here to 

 indicate them, Siebold was prepared to make his experiment. 

 In the nest from which he wanted an answer to these questions, 

 " can unfertilised Polistes females lay eggs which will develop ?" 

 and if so, "of what sex will the partheaogenetically produced 

 progeny be?" he proceeded to destroy the queen and all the 

 eggs, larva?, and pupa; in the cells with the greatest care as late 

 as possible in the season, so as to have as large a colony as 

 possible left, the limit of the time being given by the date ot the 

 appearance of the first drone. The queens thus taken were 

 used for careful histological study of the generative organs, and 

 since in all cases Siebold found the liceplaculiint scinhiis filled 

 with moving spermatozoa, he was able to feel assured that he 

 had really removed the queen in each case. We will merely 

 direct the attention of those interested in histology to the minute 

 description here given of the ovary, which in the main agrees 

 with Leydig's, and of the iweplaiitliim scnnnis, which in opposi- 

 tion to Leydig, on account of its nerve supply, Siebold holds to 

 be contractile. Alter waiting some days Siebold had the grati- 

 fication of finding the first eggs laid in the cells of several of the 

 nests from which he had removed queen, eggs, and hrvLi;, and 

 he felt convinced that they could only have been laid by the 

 small virgin workers who alone tenanted the combs. The whole 

 affairs of the colonies proceeded just as well as when the queens 

 were there, and the virgins watclied and worked with the same 

 assiduity as had done their queen-mother. In some cases 

 Siebolil actually saw a worker deposit an egg, and such egg- 

 laying workers, when anatomically tested, Showed, firstly, in the 

 presence of corpora lnU\i (the precise signification of which the 

 mvestigator had ascertained by his histological studies of the 

 ovary) that eggs had been extruded, and, secondly, in the com- 

 plete absence of S]iermatozoa from the rcccptaciilnm scininis, that 

 the insect was a virgin. Out of a hundred nests which he had 

 begun to observe in one season, and out of one himdred and fifty 

 in another, only some twenty or so in each case came through all 

 the long series of accidents from weather, insects, birds, &c., to 

 which they were necessarily exposed, and some of those which 

 promised the best results and had cost the most pains came to a 

 bad enil in the very last days of the research. In order to deter- 

 mine the sex of the wasps born from the eggs laid by the 

 parthenogenetic females, Siebold in most cases only allowed the 

 development to proceed sufficiently far to enable him to recognise 

 the sex by anatomical investigation. The dried skin, however, 

 of such grubs as were found dead in their cells afforded sufficient 

 evidence of the sex. In all cases the parthenogenetic offspring 

 was without exception male. The queen-wasps as we have 

 mentioned also late in the season lay eggs which produce drones, 

 which are easily distinguished from the drones parthenogenetically 

 produc.'l by their larger size. It occurred to Siebold when he 

 first ascertained that the queens produce drones that such drones 

 might visit his virgin colonies, and thus his whole experiment be 



nvalidated. He was, however, reassured on this point by a 

 nearer acquaintance with the Polistes ; for sucli drones are not 

 born till later than the period at which his small females laid 

 their eg^s, the former event taking place at the end of July, the 

 latter at the beginning ; and, furthermore, as we have noticed 

 above, it is not till still later (August), when the experimental 

 cells were long since all occupied with eggs, that the power and 

 desire of sexual activity comes to these drones. 



E. R. Lankester 

 (7i be conliiiued.) 



ON INSTINCT* 

 YSJWll regard to irstinct we have yet to ascertain the facts. Do 

 ' ' theanimslsexhibituntaughtskillandinnateknowlcdge? May 

 not the supposed examples of instinct be after all but the results 

 of rapid learning and imitation ? The controversy on this subject 

 has been chiefly concerning the perceptions of distance and 

 direction by the eye and the ear. Against tlie instinctive charac- 

 ter of these perceptions it is argued that, as distance means 

 movement, locomotion, the very essence of the idea is such as 

 cannot be taken in by the eye or ear ; that what the varying 

 sensations of sight and hearing correspond to, must be got at by 

 moving over the ground by experience. The results, however, 

 of experiments on chickens were wholly in favour of the instinc- 

 tive nature of these perceptions. Chickens kept in a state of 

 blindness by various devices, from one to three days, when 

 placed in the light under a set of carefully prepared conditions, 

 gave conclusive evidence against the theory that the perceptions 

 of distance and direction by the eye are the result of assoc iations 

 formed in the experience of each individual life. Often, at the 

 end of two minutes, they followed with their eyes the move- 

 ments of ci'awling insects, turning their heads with all the pre- 

 cision of an old fowl. In from two to fifteen minutes they 

 ])ecked at some object, showing not merely an instinctive percep- 

 tion of distance, but an original ability to measure distance with 

 something like infallible accuracy. If beyond the reach of their 

 necks, they walked or ran. up to the object of their pursuit, and 

 may be said to have invariably struck it, never missing by more 

 than a hair's-breadth ; this, too, when the specks at which they 

 struck were no bigger than the smallest visible dot of an 2. To 

 seize between the points of the mandible at the very instant of 

 striking seemed a more dilficult operation. Though at times 

 they seized and swallowed an insect at the first attempt, more 

 frequently they struck five or six times, lifting once or twice be- 

 fore they succeeded in swallowing their first food. To take, by 

 way of illustration, the observations on a single case a little in 

 detail : — A chicken at the end of six minutes, after having its 

 eyes unveiled, followed with its head the movements of a fly 

 twelve inches distant ; at ten minutes, the fly coming within 

 reach of its neck, w-as seized and swallowed at the first stroke ; at 

 the end of twenty minutes it had not attempted to walk a step. 

 It was then placed on rough ground Avitliin sight and call of a 

 hen, with chickens of its own age. After standing chirping for 

 about a minute, it went straight towards the hen, displaying as 

 keen a perception of the qualities of the outer world as it was 

 ever likely to possess in after life. It never requii'ed to knock its 

 head against a stone to discover that there was "no road that 

 way." It leaped over the smaller obstacles that lay in its path, 

 and ran round the larger, reaching the mother in as nearly a 

 straight line as the nature of the ground would permit. Thus it 

 would seem that, prior to experience, the eye — at least the eye 

 of the chicken — perceives the primary qualities of the external 

 world, all arguments of the purely analytical school of psycho- 

 logy to the contrary, notwithstanding. 



Not less decisive were experiments on hearing. Chickens 

 hatched and kept in the dark for a day or two, on 

 being placed in the light nine or ten feet from a box 

 in which a brooding hen was concealed, after standing 

 chirping for a minute or two, uniformly set off straight to 

 the box in answer to the call of the hen which they had never 

 seen and never before heard. This they did struggling through 

 grass and over rough ground, when not able to stand steadily on 

 their legs. Again, chickens that from the first had been denied 

 the use of their eyes by having hoods drawn over their heads 

 while yet in the shell, were while tlius blind made the subject of 

 experiment. These, when left to themselves, seldom made a 

 forward step, their movements were round and round and back ■ 



* Paper read before the Eritish Associ-ilion, Section D (Dep.irtment of 

 Zn\o:y .ind Bjlany), Augiiil 15 li, by D. A. Sp.ilJing. 



