52 



BRITISH ANTS. 



of its nervous system : the power of memory (i.e. recalling past 

 sensations and being " oriented " by them) in greater or le 

 development is hereditable, and includes reflex and instinctive 

 stimulations, differing only in their comparative simplicity or com- 

 plexity. 



Enough has been said to show that ants are not merely reflex 

 machines ; they possess senses somewhat similar to ours in effect, 

 though not in degree, and in many of their actions they are in- 

 fluenced by education, experience, and memory. 



GEOGRAPHICAL DISTRIBUTION. 



Ants are the most dominant of insects, their species are the 

 most widely distributed, they outnumber in individuals all othei 

 terrestrial animals, and they range over the whole world between tht 

 extreme Arctic and Antarctic regions. These insects are by fo 

 most abundant in the tropics forming there a powerful factoi 

 against which animals and plants have to contend and becoming 

 less numerous and important the nearer they approach the poles. 



The ant fauna of the Palaearctic region proper (i.e. not including 

 the Mediterranean region) is relative to its large size, the pooresl 

 in the world. Considerably the largest ant fauna is the Neo- 

 tropical, and next to it in numbers comes the Hindu-Malayan. 

 A great relationship exists between the ants of the Nearctic am 

 Palaearctic regions, an equally great difference being found betweei 

 those of the Nearctic and the Neotropical, the Neotropical and 

 the Aethiopian, etc. 



It is curious that some species in the extreme northern am 

 southern faunas are very much alike ; this is not on account of 

 relationship but has been brought about by convergence, througl 

 the effects of a similar climate, etc. 



GEOLOGICAL RECORD. 



Fossil ants first make their appearance in the Tertiary period. 

 Sharp states that they are amongst the earliest Hymenoptera, am 

 that remains of these insects in the Lias of Switzerland, and in the 

 English Purbecks have been referred to ants. Handlirsch, however, 

 has shown that those of the former formation certainly do no1 

 belong to the Hymenoptera, but presumably to the Homoptera, 

 and that the latter (two wing impressions from the lower Pur- 

 becks of Durdlestone Bay, considered by Westwood to belong 

 ants and described by him in 1854 as Formicium brodiei am 

 Myrmicium heeri) belong to saw-flies. 



Still the remains of ants are so numerous in the early Tertiary, 

 where the males, females and workers are as sharply differential 



