DISTRIBUTE INSECT VARIETY, 297 



colour — a circumstance that may be doubtless regarded a record 

 of the influx of cold. 



The proof of the law of adaptation of form to circumstances 

 has hitherto mainly rested on the conclusions of the general 

 zoologist and geologist, and on such phenomena as we may 

 witness in the prime wings of the table chicken and splint bones 

 of the favourite mare. For who may now-a-days doubt but 

 .that the first-named muscular delicacy is aught but the result of 

 prolonged domesticity, terrestrial habit, and inaction of the limb, 

 or that the little spilikins in the second instance are but the rudi- 

 ments of a five-fingered foot ? We know that the early Tertiary 

 horses that roamed the Northern Hemisphere had these five toes, 

 and we can now, thanks to a series of fossil remains lately 

 discovered, trace each of them in process of time dwindling to 

 a splint bone, and eventually disappearing. So when we turn to 

 insects, how endless are the vestiges of parts we behold, and 

 how endless the adaptation, although only in a few cases, 

 indeed, can the laws evoking them be truly indicated ! Here we 

 witness various perfection of metamorphosis; tassel fore and 

 hind legs in butterflies and moths, sometimes allotted to a sex or 

 characterising a group; rudimentary wings, elytra, semi- elytra, and 

 hemi-elytra; rudimentary eyes, auditory organs, musical organs, 

 modified segments. The whole being bears the appearance of 

 having passed and re-passed through changing moulds, in 

 harmony with ever-varying geographical features and configura- 

 tion. For is it not in beetles that live darkling that the eyes 

 are abridged, and in cavern and ant-hill dwellers that they are 

 absent ? Have we not shown winged insects become apterous or 

 gain ampler pinions by distribution ; and do not they everywhere 

 accommodate themselves to the varied circvimstanees of life in 

 which they are, so to speak, placed by Providence ? 



These phenomena of variation in the insect world, again, 

 appear to be presided over by certain laws of natural harmony, 

 termed Natural Selection. It is said this proneness to produce 

 capricious local or temporary variety, observable in species or 

 genera when arranged systematically in a cabinet drawer, is due to 

 an inherited tendency to produce sports, which as they from time to 

 time mimic the surrounding earthy tints, the summer's glow and 

 purple shade, or lurid and brassy reflections of the fresh sea, the 



