2IO 



AJV ECONOMIC ENTOMOLOGY. 



Fig. 203. 



this applies as well to other species infesting tree-trunks, — e.g.^ 

 the locust-borer, — is mechanical, the trunk being covered or 

 coated by some material impenetrable, repellent, or destructive 

 of or to the adults, thus preventing oviposition. The most 

 satisfactory and lasting measure, all things considered, is cover- 

 ing the lower portion of the trunk with wire mosquito-netting, 

 tying at the top and hilling up against it at the bottom. The 

 netting should extend at least two feet up the trunk and above 

 that a coat of whitewash should be maintained during the danger 

 season. Other measures, equally useful here, have been already 

 referred to when speaking of the ' ' flat-headed borers. ' ' 



In the genus Oncideres we find a curious and interesting egg- 

 laying habit : the beetle lays an egg in a twig or branch, and 

 then girdles it at a little distance below, eating 

 so far through that a high wind brings it down. 

 The twig wilts at once and the wood is then in 

 the exact condition desired by the larva, which 

 undergoes its transformations undisturbed by 

 growth or undesired moisture. Sometimes 

 shade-trees are attacked ; but merely gathering 

 and burning the fallen wood keeps the insects 

 in check. 



There are many other longicorns in our fauna, 

 nearly six hundred species being listed in the 

 catalogues, and many are beautiful as well as 

 interesting. The few species referred to here 

 do not even illustrate all the different types, 

 but are all that are sufficiently injurious to be 

 referred to at any length. Wooded regions 

 furnish the greatest variety of species, and all 

 portions of the trees furnish support for their 

 larvae. 



The family ChrysomelidcB, or leaf-beedes, contains species 

 that, in the main, feed upon leaf- tissue in the larval as well as 

 adult stages, and many of them attack cultivated crops. The 

 beetles may be distinguished by the tarsal structure already 

 described, by their usually moderate or small size, short antennae 

 which are not situated on frontal prominences, and by their 

 usually margined, not cylindrical prothorax. The larvae vary 



The "twig-gird- 

 ler," Oncideres cin- 

 gulatus. — a, beetle 

 at work ; b, egg- 

 puncture ; c, gird- 

 ling done by beetle ; 



egg. 



