mopolitan. It is amphigeic, for it extends from California 

 through America beyond the Atlantic into Mediterranean Europe 

 and Asia, while D. EiipJwrbice is scarcely ever found beyond 

 the limits of the most central part of Europe, but there in great 

 numbers. In fact its habitat coincides with the habitat of Eu- 

 phorbia Esiila. 



D. Gain adapts itself to plants of different families. It 

 forms, therefore, part of the fauna of Europe, Asia and North 

 America, and is, besides D. Lineata, the only instance of an am- 

 phigeic Sphinx. 



J). Niccea, Dah/ii, Hippophaes, and Vespcrtilio are restricted in 

 their food plants, consequently they are restricted in their habi- 

 tat too. 



Notwithstanding the roaming propensities of the indi- 

 viduals and their power to bear changes of temperature, the 

 species themselves are strictly enclosed between certain isother- 

 mal and isochimense, because the larvae do not possess the 

 same power of endurance in regard to clim.atic changes as the 

 imago does. And this is perhaps the cause that all the immi- 

 grations of AcJierontia Atropos before alluded to never succeeded 

 in forming colonies. 



Another peculiarity in the geograhical distribution of 

 Sphinges may be derived from the same cause. The species of 

 the Northern and of the Southern temperate zones are almost 

 always distinct. Although these species invade the tropics 

 from both sides, they never seem to be able to cross them so far 

 as to reach the opposite temperate zone. The geographical distri- 

 bution of some Macrosila and CJiacrocainpa is not a real excep- 

 tion, for their original home is the tropics, from whence they extend 

 north and south. Perhaps some exception from this rule may 

 be discovered in South Africa. The specimens of a so-called 

 M. Convolvnli, which I have received from New Zealand, differ 

 very materially from the European and North African insect and, 

 are evidently the type of a new species. 



As to the tropical species themselves, none of them are 

 amphigeic. It may be, that in the course of time M. qiiinqucina- 

 cuiata, now beginning to form colonies on the Sandwich Islands, 

 will reach the Australian continent, a feat that has been accom- 

 plished by one of our Diurnals {Danais Archippus). 



The extratropical species of the Southern Hemisphere, at 

 least so far as they are known, are distinct, each continent pro- 

 ducing its own species. 



