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of mackerel or herrings. Sardines have deserted the "West coast of 

 France, and the humble sprat disguised in various ways is placed upon 

 the breakfast table instead of its more aristocratic relative. Per contra, 

 the Sturgeon once a royal fish from its scarcity, and one accustomed to 

 cool waters, is commonly seen on our fishmongers' slabs, and the 

 Norwegian or small red lobster, is seeking a home on our shores. Could 

 stronger proof be urged than this fact of changes of habit in these 

 creatiu'es ? Well, if it be required, it is forthcoming by descending a 

 little lower in the animal kingdom, amongst the examples we should 

 imagine pre-disposed to resent any change of climate. 



Every one knows a white butterfly by sight, even the London street 

 arab has occasionally a chase after one, and the most casual obseiwer 

 will have noticed that after a time as spring turns to summer, these 

 butterfliei, which at first pleased our eyes by their brightness, become 

 ragged and worn, until at last but few appear upon the wing ; then their 

 numbers increase again gradually as they are renewed by specimens fi'om 

 fi'esh stocks, and in August we see more than ever. This is owing to 

 our warm months allowing the eggs deposited in May to develop once 

 more to the perfect insect, and for the progeny of these again to pass 

 through their minor metamorphoses before the end of the summer. 

 Whenever this phenomenon occurs in natui'e we call the insects affected 

 by it double brooded. That is, one whole round of the life history is 

 accomplished the same year that the egg is laid, one complete cycle in 

 fact and two-thii-ds of another, in other words two broods of insects and 

 two sets of caterpillars, but only one of the chrysalis. 



Many of our insects are thus two-brooded in the South of England, 

 but as we proceed northwards we find such occurrences less common, or 

 reduced to single summer appearances, although the same species in 

 confinement, kept at an equable temperature, will produce three and some- 

 times more families in the year, thus clearly showing that the number is 

 governed by favorable or non-favorable surroundings. Here, then, is a 

 simple fact, well known to every entomologist. What shall we learn 

 by looking a little closer into the working of it ? 



Of our annually captured 56 British butterflies, only 17 are claimed 

 in our books as double-brooded, namely, four whites, three browns, two 

 ranessas, five blues, one copper, and two skippers. In addition to these, 

 we may add, if you please, three more, which are but casual visitors, by 

 which we mean, that they cannot certainly, be reckoned on to occur every 

 year, although frequently taken in England. Of these three,* our 

 specimens when captured are almost invariably of the second brood, the 

 first being wanting, whereas fifty years ago, when equally scarce, it was 

 possible to capture them at either or both times. One of these butter- 

 flies was certainly a constant double-brooded species one hundred years ago, 

 and although exci-edingly local, not rare where it occurred; in Haworth's 



* Daijlidice, lathoiiia, edusa, the Bath white, Queen of Spain, and Clouded 

 yellow. Edusa is frequently seen in early summer, but as hybemated gpecimeus. 



