18 ZOOLOGICAL GEOGRAPHY. [part. hi. 



Macrodontia; and Titanus, the largest insect of the entire 

 family. 



Of the Cerambycidse there are 233 genera, exceeding by one- 

 half, the number in any other region ; and 225 of these are 

 peculiar. Only 2 are common to the Neotropical and Nearctic 

 regions exclusively, and 3 to the Neotropical and Australian. 

 The most extensive genera are the elegant Ihidion (80 sp.) ; 

 the richly-coloured Chrysoprasis (47 sp.) ; the prettily-marked 

 Trachyderes (53 sp.) ; with Odontocera (25 sp.); Criodon (22 sp.) ; 

 and a host of others of less extent, but often of surpassing 

 interest and beauty. The noteworthy genera of wide range are, 

 Ocme and Cyrtomerus, which have each a species in West Africa, 

 and Hammatocerus, which has one in Australia. 



The Lamiidse have 219 genera, and this is the only tropical 

 region in which they do not exceed the Cerambycidse. This 

 number is almost exactly the same as that of the Oriental 

 genera, but here there are more peculiar groups, 203 against 160 

 in the other region. The most extensive genera are Hemilophus 

 (80 sp.), Colobothea (70 sp.), Acanthoderes (56 sp.), Oncoderes 

 (48 sp.), Lepturgus (40 sp.), Hypsioma (32 sp.), and Tceniotcs 

 (20 sp.). Macropus longimanus, commonly called the harlequin 

 beetle, is one of the largest and most singularly-marked insects 

 in the whole family. Leptostylus has a single species in New 

 Zealand ; Acanthoderes has one species in Europe, W. Africa, 

 and Australia, respectively ; Spalacopsis has a species in W. 

 Africa; Pachypeza is common to S. America and the Philip- 

 pines ; Mesosa is Oriental and Palsearctic, but has one species on 

 the Amazon ; Apomecyna ranges through the tropics of the 

 Eastern Hemisphere, but has two species in S. America ; Acan- 

 thocinus has one species in Tasmania, and the rest in South 

 America, North America, and Europe; Plioca is wholly Neo- 

 tropical, except two species in the Philippine Islands. 



General Conclusions as to the Neotropical Insect-fauna. — 

 Looking at the insects of the Neotropical region as a whole, we 

 are struck with the vast amount of specialty they present ; and, 

 considering how many causes there are which must lead to the 

 dispersal of insects, the number of its groups which are scattered 



