THEIR RELATION TO PLANTS 67 



but the posterior four joints only. It includes a great 

 variety of species, many of tlicm of sombre, uniform 

 color, shunning the light, living in concealment and 

 often or even generally feeding on dead or dry vege- 

 table matter. Yet there are exceptions to this, as for 

 instance the blister beetles which, in the larval stage, 

 are semiparasitic, and as adults feed ravenously on 

 vegetation. When they are feeders on living plants, 

 however, it is as straight-forward devourers of leaf 

 tissue that they appear, and they do not threaten the 

 existence of the plant attacked, however much they 

 may injure it for the farmer's purpose. 



And now we get the Rhynchophora or snout beetles 

 which, broadly speaking, include the bark beetles or 

 Scolytids and with them some of the most dangerous 

 enemies to plant life. Popularly most of these species 

 are known as weevils and, so far as I am aware, all of 

 them are plant feeders. And there is no part of the 

 plant from root to tip that is not attacked; no 

 stage from seed to pollen that is not eaten by them. 

 They are among the oldest of the Coleoptera in the 

 geologic record and have adapted themselves to life 

 on vegetation under all sorts of conditions. The term 

 snout beetles calls attention to one of the most prom- 

 inent external structures — the elongated head drawn 

 out into a beak of varying length, at the end of which 

 the small mouth parts are situated. For feeding pur- 

 poses these do not seem to be especially well designed, 

 indeed in many species the mandibles are deciduous 

 and are shed soon after the adult is developed; but 

 for hiding and placing the eggs no better nor more 

 practical tool can be imagined. For instance, almost 

 every one that has gathered nuts has had the experi- 

 ence of finding some of them wormy, with absolutely 

 no trace of an opening on the outside to show how 



