73 



species, for there are about it great callous ridges from near tlie 

 ground to up on the larger branches. 



Figure 55. 



Tree cricket. 



ORTirOPTERA. 



This group, altliough it contains manv insects that are exceed- 

 ingly destructive to crops, contains few that injure trees, and I 

 know of only one that infests the elm, and this is nowhere, I 

 think, very troublesome. This is the, 



TREE CRICKET. 



It is not a very common insect here, though perhaps more so 

 further south. Figure 55 gives a view of the 

 male of this species. CEcaiithus niveus^ Serv. 

 It is more destructive to raspberries and grape- 

 vines. The males are white and the females 

 sometimes white, sometimes dark. The insect 

 is allied to the common cricket, and is able to 

 produce verv loud, shrill chirping. The female 

 pierces with her ovipositor the canes of rasp- 

 berry or wood of small branches, peach or grape 

 or elm, and deposits her eggs in thepeth. These punctures are in 

 a row and may so weaken the twigs that they break off. The in- 

 sect does not eat any part of the plants which it infests and the in 

 jury which it does is purely mechanical. They are also to be 

 ranked with beneficial insects, for the lai"vae feed upon plant lice 

 and other small insects. Whether they on the whole do more 

 harm than good I do not know. 



HKMII'TEI^A. 



To this group, which embraces some of the most simply or- 

 ganized insects and the lowest in rank, belong some verv de- 

 structive species. All the insects of this group uliich we shall 

 consider are small, most of tliem microscopic, and tlieir life his- 

 torv is very complex and obscure. Those which infest the elm are 

 such as are commonlv known as plant lice. No group of insects 

 contains so manv species which are likely to be overlooked be- 

 cause of their minute size and because they hide in crevices of 

 Ixu'k and similar locations, and this is the more unfortunate be- 

 cause, when once established, they multiply prodigiously and soon 

 overrun a tree to such an extent that their removal involves much 

 labor. The amount of injury whicli any single plant louse, or 



