LAMELLICOUNIA. 21 



respectivel)^ living and feeding in the nests of those insects. Such 

 a habit is generally accompanied by very marked peculiarities of 

 structure, often so great as to completely obscure the real relation- 

 ships of the species. The Ceemastochilini, of which a number 

 are described in the present volume, are good examples of these 

 interesting insects. It seems probable that these feed upon the 

 substance of the nest in defiance of its proper inhabitants. They 

 generally pi*esent a curiously compact and invulnerable exterior, 

 ^vhich evidently serves to secure them against attack. Whether 

 their larvce possess any corresponding adaptation is unknown. 

 Another group appear to act as scavengers of the nests in which 

 they live, or are otherwise serviceable to the proprietors and are 

 not molested by them. The curious OntJiopJiagns myrmecopMlus, 

 which inhabits the nests of Pheidologiton in tree-trunks, may be 

 inferred, from the habits of the genus to which it belongs, to have 

 a scavenging function there. 



Most remarkable of all are those forms which have a special 

 apparatus for the secretion of a fluid, for the sake of which they 

 are prized and tended by their hosts. Two Indian genera at 

 least, Coryilioderus and Ciicetopistlies, belonging to the Subfamily 

 CoPRiiSr.^, are of this class. In these certain deep cavities exist in 

 the prothorax or elyti'a into which secretory glands open and from 

 which spring tufts of bright yellow hairs. The fluid probably 

 flows over these hairs and is licked off by the Termites with which 

 tlie various species of these two genera live ; or possibly the hairs 

 are connected with a nervous apparatus and their stimulation by 

 the Tei-mites promotes the secretion. The organs of the mouth 

 are degenerate in the beetles, an indication that they ai'e fed by 

 their hosts ; and from exactly similar phenomena in quite other 

 groups of beetles, it can safely be assumed that the secretion is 

 regarded as a luxury by the hosts and for its sake the beetles and 

 their young are cherished and all their wants supplied. 



Classification. 



It will be found that in the course of this work methods of 

 classification more or less at variance with those at present adopted 

 have been introduced, and names of genera and species now in 

 frequent use are rejected with a freedom that may not find 

 general approval. The classification here adopted does not pretend 

 to finality in its details, but only to convenience, for the time 

 when knowledge of the constituent forms of any group of Lamelli- 

 cornia will even approach completeness is yet far off, and, as new 

 forms reveal themselves, apparent breaks of continuity must dis- 

 appear and revision of the limits of the groups which sysremati- 

 sation renders necessary be continually repeated. Genera and 

 larger divisions are therefore arbitrary and their most convenient 

 limits must remain a matter of opinion. The system which has 

 been adopted of expressing in tabular form the most salient differ- 

 ential characters of every species, genus and larger division has 

 provided a crucial test of existing groupings and entailed a con- 

 sistency which is not to be expected from the short memoirs by 



