20 RIIOPALOCERA N I MONICA. 



The second peculiarity which is noteworthy is that the upper and undersides of the wings are utterly 

 different, presenting a startling contrast. This is of great service to them as a protection from their 

 numerous enemies. I have often watched a dragon-fly attempt to catch one of the Blues, but never saw a 

 capture made; when in flight the Blue at a distance presents only the impression to the eye, of a blue 

 substance moving along irregularly, but if viewed closer the rapid irregular flight of the insect brings 

 alternately into view, greyish-white and blue (or brown in the female). The dragon-fly makes a succes- 

 sion of dashes at his trey, which, if hard pressed, will settle with closed wings, presenting an entirely 

 new appearance, when the baffled pursuer almost invariably abandons the chase. 



The third peculiarity is that some of the species are single-brooded, others many-brooded, during the 

 year. In the foregoing table I have placed the figure (i) against the species which only appear once, the 

 figure (2) against those that appear many times in the year, and (?) against those of which I have no information. 

 I have obtained from the table the following result, namely, those that appear once are all without 

 exception tree-feeders, and those that appear many times feed on low plants or creepers ; after studying 

 the structure and habits of the larvx of many of the species, I find that they are very slow in their 

 movements, and all have very small heads, with weak jaws, and can only feed on young fresh leaves. 

 The trees they feed on only throw out new leaves regularly in the spring, but low plants and creepers 

 grow all the year, from early spring until late in the autumn ; therefore, the tree-feeding species 

 can only obtain their food, in a fit stage for eating, once in the year, and are necessarily single-brooded; 

 those which feed on lows plants can do so from March to October, and are therefore many-brooded. This 

 law, however, cannot be applied to other genera which have powerful jaws, and appear only once 

 in the year and the fact of such being only single-brooded depends upon other circumstances, namely, 

 either the structure, coloration, or habits of the imago, which may render them especially liable to be 

 captured by what I term "general enemies" such as bats, spiders, and dragon-flies. Thus with the 

 Hyberniadae, which always appear in the imago, and lay their eggs in the winter months. These eggs 

 soon hatch, and the larva feeds up for a short time and then changes to pupa, remaining in this stage 

 all the summer, autumn, and until the next winter. I think the reason is obvious. All (\\efeiiHitc 

 Hyberniadae are either apterous or only have wings incapable of flying, whilst the males, although they 

 have very largely developed wings, are somewhat clumsy fliers, rendering them very liable to capture 

 by dragon-flies, if disturbed in the day time, or to become entangled in the nets of spiders at night; ice 

 therefore find them only appearing in the perfect state when it is too cold for any of these enemies. 

 Again Tseniocampse, which are strong robust moths, only appear in the spring; these have the habit of 

 buzzing about trees, and they would be rapidly exterminated if they appeared later on, when spiders' webs 

 cover every bush and bats are abundant. I believe that when the life-history of any insect is attentively 

 studied, we shall be able to assign the reason of its single or multiple appearance accurately. 



