July J, 1870.] 



HARDWICKE'S SCIENCE-GOSSIP. 



149 



be his food), and in many cases this is so, yet there 

 are puzzling exceptions. The mother insect, too, is 

 careful to deposit her eggs in such a place (usually) 

 that the caterpillars, immediately they require it, 

 can obtain their appropriate food ; and we find, in 

 confinement, that it is necessary to actually place 

 the very young larvae on the leaves or flowers they 

 should feed upon. Thus, sometimes a brood of 

 young caterpillars will emerge in a box, and the en- 

 tomologist might place twigs very near them, but 

 the probabilities are that they will not find their 

 way to these, either by smell, or by sight ; and may 

 actually starve close to plenty. So, also, as larvae 

 increase in size, we often find that when fresh food 

 is introduced, and placed beside those on which they 

 are feeding, they will obstinately persist in clinging 

 to that which is stale, and have at last to be re- 

 moved from it. Therefore, in the case of a number 

 of species, it is better to remove them from the 

 twigs or leaves which have become unfit for their 

 food, and place them upon those which we substi- 

 tute. 



Another singular circumstance in the case of some 

 newly-hatched larvae is this ; that for hours, or per- 

 haps for days, they show a strong inclination to 

 wander about. The Loopers, or Geometers, are es- 

 pecially given to this, and will go "looping," or 

 "straddling " about at an unpleasant rate, neglect- 

 ing their food, and seemingly inflicting annoyance 

 on each other, when they happen to come into con- 

 tact ; for such a piece of politeness as standing out 

 of the way to let another individual pass is unknown 

 in the realms of insect life. However, if one does 

 not move, the other is at no loss what to do, but 

 coolly steps upon the obstructing individual, and in 

 certain species the result is that they attempt to 

 bite, or actually do bite each other. The young 

 Bombyces, of several species, are also sadly sure to 

 wander about in a very purposeless manner ; so that 

 we are placed in circumstances of difficulty with 

 these, it being needful that caterpillars should have 

 a certain freedom of locomotion, or else they will 

 not thrive, and yet it does not do to allow the.m to 

 stray off their food-plants at their pleasure. This 

 may be taken sometimes, though, as an indication 

 that the leaves, or other food with which they are 

 fed, does not suit their taste, and then some change 

 should be tried. A little trouble is occasionally 

 given by another circumstance, that, in the instance 

 of some plants and trees, when the leaves are 

 gathered with a slight film of moisture upon them, 

 it appears to prevent, at least in breeding-cages, 

 the larvae from obtaining a firm hold of the leaves 

 with their claspers, and yet it is so very little in 

 amount that it can hardly be removed. In trans- 

 ferring larvae from one twig to another, I have 

 sometimes had an individual roll off several times 

 before he could be safely located on his fresh pro- 

 vender. A precaution must also be taken with 



some species which are very fond of dropping by a 

 silken thread. Most species will, indeed, do this, 

 under stress of circumstances ; but there are some 

 kinds particularly apt thus to throw themselves off 

 their food, at a slight alarm ; nor can they always 

 recover themselves with readiness. Thus, in re- 

 moving larvae of the scarce "Vapourer {0. gono- 

 stigma), while young, by the aid of a camel's-hair 

 pencil, I have found that it will not do to attach 

 them by these threads to a leaf, and leave them to- 

 regain their equilibrium. This they frequently fail 

 to do, and may be found some hours afterwards 

 sometimes still swinging round and round, as if they 

 were being roasted, — the issue being death, or a 

 serious check to the growth of the caterpillar. 

 Neither should caterpillars be shifted from one 

 place to another, nor in any way disturbed, while in 

 the act of undergoing their changes of skin, at which 

 time they deem quiescence desirable. Exceptions 

 occur amongst the Geometers ; a few caterpillars of 

 this family perambulate about during the interval 

 they are awaiting the change, though not eating. 

 But we are not surprised at an erratic tendency 

 showing itself amongst our friends the "Loopers," 

 whose slim bodies are so particularly adapted for 

 locomotion. It is desirable, at least in the case o£ 

 caterpillars which are of rarity, that at the changes 

 of skin they should be protected from the annoyance 

 they would be likely to get from others, even of 

 their own species, by separating them for the time. 



In feeding caterpillars their peculiarities should 

 be studied. There are some that, after eating, seem 

 to prefer to hang head downwards — an odd mode 

 of facilitating digestion. Others like to have a bare 

 twig at hand, on which they can extend themselves, 

 at full length. There are others again, which retreat 

 at times to dry or withered leaves, resting on or 

 under these when not feeding. Some will form an 

 apparent attachment for one particular leaf, as was 

 the case with the larvae of a Noctua I had in 

 feeding. A dry birch leaf in one corner of the cage 

 was the regular resort of half a dozen of these, and 

 they stretched themselves side by side under it for 

 hours during the day, and exhibited as much discom- 

 fort when it was removed — so that they retreated 

 to their corner in vain—as an old gentleman of the 

 Georgian era would have felt if on retiring for his 

 nightly repose, the tassled cap which was to cover 

 his " phrenological development," had been carried 

 off! 



Caterpillar quarrels, as already hinted, will be of 

 occasional occurrence in most species when con- 

 fined. Some there are, like Trapezina and Satellitia > 

 which are well known, not merely as unfriendly to 

 others, even of their own species, but by nature 

 actually caunibals, and preferring live caterpillars to 

 vegetable food. These may be fed on common 

 species if thought desirable ; of course they mus t b 

 kept from all contact with others it is wished to 



