94 Zoologica: N. Y. Zoological Society [HI; 3 



maligna and A. foveiceps, because the coccids enabled them to 

 acquire very intimate trophic relations to the plant. The coc- 

 cids present an unsolved problem in this connection. It would 

 seem that the Tachigalia must be their true host-plant, and that 

 the various other plants on which they are known to live, are 

 subsequent, or secondary hosts, possibly acquired when the 

 natives of British Guiana and of the surrounding countries took 

 to making clearings in the jungle and growing in them various 

 introduced plants such as pine-apples, Hibiscus, etc. The truth of 

 this statement can, of course, be established only by further in- 

 vestigation of Pseudococcus hromelix throughout its range. 

 When the obligatory ants had thus acquired their definitive at- 

 tachment to the tree, the miscellaneous inquilines necessarily 

 became restricted to its youngest stages since they were no 

 longer able to compete with the obligates for the possession of 

 nesting sites on the adult plant. The Silvanid beetles were prob- 

 ably relatively late intruders which found that they could inha- 

 bit the young tree for a considerable period before the queens of 

 the obligate ants had succeeded in maturing their broods of 

 belligerent workers. At first the beetles merely used the petiolar 

 cavities as lodgings and fed on the nutritive parenchyma in their 

 walls, but later they discovered the coccids and learned how to 

 obtain their honey dew and came to depend more and more on 

 this saccharine nutriment. The various parasites, scavengers, 

 etc., which infest the beetle colonies and their droves of coccids 

 obviously represent still more recent accessions to the biocoenose. 

 The other insects, such as Atta cephalotes, the Membracids and 

 their attendant ants, the caterpillars and gall-flies of the leaves, 

 etc., may belong to the ancient miscellaneous fauna which origin- 

 ally attacked or frequented the Tachigalia in all its stages, when 

 it was quite as "unprotected" as the great majority of jungle 

 plants. 



Turning now to a consideration of the beetles themselves, 

 it would seem to be desirable to review their activities in the 

 light of what is known concerning the other members of the 

 natural family to which they belong. Here, however, we en- 

 counter difiiculties, for the family Cucujidse {sensu lato) has been 

 more neglected by taxonomists and students of insect behavior 

 alike than any other family of equal size in the order Coleoptera. 



