DISTRIBUTE INSECT VARIETY. 313 



led to observe and ponder how truly contrary to all natural law 

 and possible definition the proposition of two living things being 

 wholly alike has ever been, we can but allow the rosy charm and 

 dropping perfume to be things alike oi-ganically chemic and 

 plastic in their nature. Nor does the classifier find his ideal 

 species nearly so averse to uniting with their far-off affinities as 

 might be supposed. Mules are freely obtained by German dealers 

 and by those that possess the floral fancy, from the ruddy Poplar 

 and Eyed Hawks of our parterres ; * and even the swift-darting 

 Vollucella Flies of the damp woodland, if we can credit a commu- 

 nication once made by Mons. Lapelletier de Saint Fargeau to the 

 Academic des Sciences, unite very well together. In natural 

 conditions diverse species of other and very various orders have 

 been rarely found united ; as in Italy a male of the common Two 

 Spot Lady-bird with the variable Coccinella dispar ; our bramble- 

 frequenting Fritillary, Adippe, in Switzerland with its congener 

 Niobe ; and the leaf -rolling Tortrix ribeana, so common in dusty 

 July, with its blunt-winged congener cerasana. Species also flirt 

 and pair with their colour varieties, detecting the strangers doubt- 

 less by odour or music, and with the common Clouded Yellow 

 and its variety Helice this appears a source of a race of sub- 

 hybrids. Hermaphroditism, where the two halves of the insect 

 on either side of the median line represent the opposite sexes, is 

 frequent, and is found in all orders ; or again, the two halves may 

 represent type and variety. But such insects are lawless and 

 monstrous. 



Given climate and surroundings are the existing ministers of 

 change that rule the filmy insect fabric ; geology will reveal the 

 past evidence of their endless operation in the oscillations of 

 cosmogenic temperature, and in the relics that indicate the 

 shifting of their lifers drama from area to area. Let us suppose 

 one of the great changes of climate recorded on the rocks to 

 supervene, with sunken land areas and piercing cold, over the 

 Palsearctic. Now, as the circles of insect distribution gradually 

 move southward, the more noi*thern varieties, such as the blue of 

 Arthur^s Seat, would establish themselves in the south of our 



* Deilephila vespertilio, likewise, wiU cross with B. euphorbia; and D. hip- 

 pophaes ; and of the Bomhycina, Saturnia pyri with S. spini and S.pavonia. — 

 Dr. Staudintrer's Catalocrue. 



