iv INTRODUCTION. 



family, the Passalidse. Of Lucanidae we are able to record only 5 species of 3 genera, 

 whilst in Passalidse we have 67 species of 27 genera. A comparison with such allied 

 faunas in other parts of the world as have been worked out sufficiently to promise 

 approximately accurate results, seems to show that the poverty in Lucanidse arises from 

 Central America lying too far south in the continent to have been reached by many 

 species of Old-World genera, which in America extend no further south than the 

 temperate zone, and too far north for the genera characteristic of South Brazil, 

 Chili, and the Andes. The conditions seem, however, to be very favourable to the 

 Passaliclse, which here reach their highest development and exhibit more diversity of 

 form than in any other region. Other faunas show the following proportions : — North 

 America (Henshaw's Catalogue, 1885, and Suppl. 1887) possesses of Lucanidse 14 

 species of 5 genera, and Passalidae 1 species of 1 genus ; Brazil (Gemminger and Harold's 

 Catalogue, 1868), Lucanidee 22 species of 6 genera, Passalidse 25 species of 16 genera. 

 The Colombian subprovince probably approaches our fauna nearer in its proportions of 

 the two families ; but the data for an approximate enumeration, in this case, are not at 

 hand. In the tropical regions of the Old World the predominance of the Lucanidae is 

 everywhere strongly marked. In the islands of the Malay Archipelago there are 

 upwards of 80 species of Lucanidse of a dozen genera, and only about 27 Passalidse 

 of 6 genera. 



The Lamellicornia are well represented in Central America in all their families. In 

 the following pages we are able to record the large total of 1028 species contained in 

 127 genera. This is about one-tenth of the number described to the present date from 

 all parts of the world, which I find, on a rough enumeration, to be very nearly 10,000. 

 On comparing this proportion with those of the previously completed tribes in the 

 present work, we find that it is rather greater than in the Geodephaga, where the 

 numbers are 1086 : 12,000, and much less than in the Longicornia, of which Central 

 America possesses 1273 species out of the total number described, viz. 8968. A com- 

 parison of the Lamellicorn fauna with that of other tropical regions of similar extent 

 is impossible, as the necessary data do not exist in a connected form : we cannot say 

 therefore whether our fauna is exceptionally rich for a tropical region ; but as compared 

 with temperate regions, e. g. Europe and North America, it is certainly very much richer 

 than either. Of Lamellicornia Europe possesses only 636 species of 71 genera and North 

 America 523 of 75 genera. In the less tropical tribe of Geodephaga the proportion is 

 nearly reversed, our region furnishing only 1086 species, as compared with 1750 and 

 1223 for Europe and North America respectively; on the other hand, in the more 

 tropical tribe of Longicornia Central America shows a still more decided superiority, 



