108 Zoologica: N. Y. Zoological Society [III ; 3 



certain. Later, after completing their growth, they are often 

 too bulky to escape through the entrances made by the beetles, 

 and as such imprisoned coccids contain eggs, they might be 

 supposed to breed in the petioles. I have never been able to find 

 either the males or the deposited eggs in the petioles, and as the 

 total number of coccids in a petiole is too small to indicate the 

 survival of many of the young, I suspect that the beetles, though 

 averse to devouring the young or mature coccids, nevertheless 

 consume many of the eggs. How the coccids manage in the first 

 place to reach the individual Tachigalia plant is a problem which 

 presents itself also in the case of any of the other often widely 

 distributed species of the family. That ants have much to do 

 with carrying certain species of coccids to their host-plants is 

 very probable. The only other active agents in such distribution 

 would seem to be birds or the wind. 



Soon after they enter the petioles the coccids seek out the 

 strands of nutritive parenchyma, and sink their slender beaks 

 into the tissue. And as the beetles keep gnawing at the same 

 strands, grooves or narrow depressions are soon made in which 

 the coccids settle, one behind the other, in rows, with the long 

 axes of their bodies parallel with the long axis of the petiole. 

 Thus the coccids naturally and inevitably come to lie in the paths 

 of the feeding beetles, so that these can hardly avoid continual 

 contact with the waxy creatures and their excrement. Probably 

 at first the coccids simply voided their excrement in the grooves, 

 thus drenching the surface of the nutritive parenchyma, so that 

 the beetles found their bread spread with syrup. But this could 

 hardly be an unalloyed blessing, because a sticky liquid spread 

 on the walls o:^the petiole would almost certainly be injurious 

 or fatal to the eggs, pupae and younger larvse of the beetles. We 

 may therefore conjecture that the latter soon learned to stroke 

 the coccids and to swallow the honey-dew at its very source, and 

 that they have even acquired so keen an appetite for the liquid 

 that it has now become a very important if not an essential 

 constituent of their diet. The exploitation of such a constant 

 and energizing supply of syrup, moreover, would surely tend not 

 only to lengthen the original life-span of the adult beetles but 

 also to increase the number of their progeny and hence the size 

 and vigor of their colonies. This is suggested by the conditions 



