INTRODTICTIOlSr. XXVll 



and possess a luxuriant A'egetation. Moreover, tbe present writer 

 has worked out a large portion of the llhynchotal fauna of the 

 two areas. 



The following is a comparative statement of the genera and 

 species belonging to the families treated in this volume : — 



Comparison of a portion of the RhyncJiotal Faunas of British India* 

 and Central America t. 



Pam. Pentatomidae . . British India. . . . Genera 199, Species 541 

 Central America . ,, 104, „ 384 



Fam. Coreidae British India. . . . Genera 45, Species 143 



Central America . „ 72, „ 206 



Pam. Berytidae .... British India .... Genera 3, Species 4 

 Central America . „ 3, „ 4 



It will thus be seen that in the Pentatomidoc British India is far 

 richer in genera and species than Central America, while in the 

 Coreidtc the proportion is reversed ; the Berytidae of the two areas 

 are very similar in numbers, but most probably we know very little 

 of the family in either region. In Pentatomidae, British India is 

 apparently the most prolific region in the world. 



Perhaps no palaeontologists have more reason to complain of 

 the imperfection of the geological record than those who study 

 the insects of past times. Insect-remains are frequently badly 

 preserved, and such wing-venation as can be studied has some- 

 times led to discordant conclusions. Scudder is our first 

 authority ; and in the last edition of ZitteFs ' Text-book of 

 Palaeontology ' he writes : — " The oldest known fossil insect is 

 a somewhat obscure wing, plainly Hemipterous (Protocimece 

 silurica, Moberg), from the Graptolite Slates of the Swedish 

 Upper Ordovician." The Carboniferous evidence is conclusive. 

 Tbe presence of Ehynchota in Permian rocks is somewhat 

 open to argument, but on the whole trustworthy. When we 

 come to later times, we may refer to Scudder's ' Tertiary Insects 

 of North America,' the largest work of its kind, and one dealing 

 considerably with the Rhynchota. According to Scudder, writing 

 in 1890, the number of Tertiary Ehynehota of the whole world 

 was then estimated at 569, of which 355 were Heteroptera and 

 214 Homoptera. 



External Anatomy. — The principal structural details of the 

 Heteroptera are represented in the following outline figures of 

 Mattiphus laticolUs, Westw., a species belonging to the British- 

 Indian fauna. The structural terms here given agree with the 



"^ As enumerated in this volume. 



'Biologia Centi'ali-Americana,' Ehynehota, vol. i. 



