HARDWICKE'S SCIENCE-GOSSIP. 



2G9 



vivarium, and stocked it with insect inhabitants of 

 the usual kinds. These will be likely enough to 

 make predatory excursions amongst the dwellers 

 upon the land, and the latter have, unfortunately, 

 no opportunity for returning these attacks ; for 

 though some of them are pretty sure to make 

 acquaintance with the "liquid element," they have 

 quite enough to do to extricate themselves there- 

 from. And this is one of the drawbacks attendant 

 upon the addition of water, that the non-aquatic 

 insects will persist in tumbling into it, and the 

 friendly observer, who acts the part of the Iloyal 

 Humane Society, cannot be always at hand. 



He who has done anything in the way of rearing 

 insects through their various transformations, can- 

 not but admit that a very great preponderance of 

 larvae prefer to conceal their proceedings. Many 

 of the burrowiug and mining larvae are, from the 

 very nature of their food and their peculiar habits, 

 of necessity hidden from view ; nor could they well 

 be made objects of exhibition in any vivarium which 

 could be contrived. And with regard to the cater- 

 pillars or larvse of Lepidoptera (butterflies and 

 moths), to whicli some persons would point as good 

 examples of the fitting tenants of the Insect Viva- 

 rium, — these, though feeding often in positions 

 where they can be observed, are easily frightened 

 from their food. Sounds, agitation, or even the 

 mere approach of an on-looker, will cause at least 

 three-fourths of our caterpillars either to assume 

 some posture of defence, or at least to SAving from 

 their food-plants by silken cords. So much is it the 

 fact that caterpillars are uot likely to get on well 

 if they are liable to disturbance, that some years 

 ago, when I had a number in rearing, belonging to 

 different species, in a small ant-house, I found it 

 necessary to make an absolute rule that visitors, 

 especially juveniles, should have very infrequent 

 admission. This would apply just as much to any 

 vivarium which, while so contrived as to embrace 

 within it a variety of larvae as well as of imagos, is 

 intended for public exhibition. However much we 

 may regret it, it is nevertheless true, that many of 

 the most interesting amongst the insects cannot be 

 watched without much caution and patience, so 

 anxious are they to conceal their proceedings from 

 public view. A notable instance suggests itself in 

 the economy of the bee, and though formicaries 

 may be contrived, in whicli the proceedings of ants 

 can be observed to an extent, much that goes on is 

 hidden from public gaze. But only fancy an Insect 

 Vivarium of large proportions, erected for the in- 

 spection of that very careless animal the British 

 public ! TVe will suppose that its managers stock 

 it with a proportion of rare and choice species ; 

 and, for their benefit, it would be needful to have a 

 scries of notices in the vicinity, somewhat in the 

 following style:— "Coughing or loud talking is 

 strictly prohibited near the Vivarium." "Visitors 



j are requested to tread lightly when they are ap- 

 j proaching the Vivarium." "Though persons are 

 not forbidden to point at objects in the Vivarium, it 

 I is requested that no one will touch or tap against the 

 ! glass or metal work." " Those who are habitual 

 '• smokers, or who have any strong odour about 

 their person, are cautioned not to continue very 

 \ long in proximity to the Vivarium." 

 I But, returning to the question, "Do not some 

 | Insect Vivaria answer very well ? " I must confess 

 to scepticism on the point. I know several who 

 J made trial of them, and after a few months of vary- 

 ing success, have had to give up the attempt to 

 make them answer. One of the greatest difficulties 

 I found, was with regard to the plants. The viva- 

 rium cannot be kept in the open air, exposed to the 

 changes of the weather ; for several reasons it is 

 needful that it should be screened from these, 

 though, in the ordinary way, it may be desirable 

 to expose the vivarium, if not in sunshine, at least 

 to full daylight. A supply of grass is exceedingly 

 desirable, as observed by a correspondent of 

 Science-Gossip, and this will not grow to advan- 

 tage under cover. Nor is the case exceptional, for 

 a series of troublesome experiments with different 

 plants, which were required for the purpose of feed- 

 ing larvae enclosed in. the vivarium, proved to me 

 that our native plants, on the whole, will thrive for 

 bat a brief space if placed within a structure, which 

 places them under conditions corresponding to a 

 conservatory life. And another awkward circum- 

 stance is this : that if you actually feed larvae upon 

 the plants you have growing in the earth of your 

 vivarium, these soon become disfigured, and the 

 appearance they present is unpleasing to the eye. 

 Hence the expedient has been suggested, of intro- 

 ducing here and there bottles filled with water, into 

 which the twigs or branches of shrubs and stalks 

 of low-growing species are inserted, and renewed 

 from time to time. The proper adjustment of 

 these amongst the other plants is an awkward: 

 business, and the requisite changing of them quite 

 as much so, especially if the vivarium is well 

 stocked with flying insects as well as larvae. Many 

 of the latter must of course be removed with the 

 food-plants and put back again. Another annoy- 

 ance I may mention here, attendant upon larvae- 

 receiving in the promiscuous style and it is this — 

 some species require special food, not easy to obtain 

 in the right condition. You furnish them with a 

 supply of this in your vivarium, and visiting it some- 

 morning, you find, to your great disgust, that it has 

 been devoured by some " common fellows," whe 

 might have satisfied themselves with the plants on 

 which you had placed them, but ^ehose to wander 

 off, and attack a neighbour's feed. 



Experientia docet. The inference I have drawn,, 

 from personal experiment and the reports of others, 

 is unfavourable to Insect Vivaria, on either a small: 



