HEMIPTERA. 



473 



The Lygus solani (fig. 1043, Nos. 2 and 3 magnified, No. I nat. size) 

 lives on the potato leaf; and the Lygus umbcllatarum (fig. 1043, Nos. 4 

 and 5 natural size, and No. 6 magnified) lives in great quantities on 

 the Umbellatae. 



The Pentatoma oleaceum (fig. 1044) is another plant-destroying 

 insect, which is often noticed on vegetals. 



FIG. 1044. Pentatoma 

 oleaceum. 



FIG. 1043. Lygus solani and Lygus umbellatarum. 



The family of Aphides are injurious to the gardener. Some live 

 upon the leaves of plants, and suck their juices. Other kinds, as the 

 Oak Aphis, live on the trunks of trees, v/hich they pierce, and suck 

 their juices. Some live upon the tops of young shoots, as the Rose 

 Aphis ; and others feed underground, and suck the roots of plants, 

 as one species which infests the lettuce. When aphides attack a plant, 

 it generally has a tendency to rot at the roots, and I have even known a 

 large willow-tree to die down and rot after a severe attack by aphides. 

 Gardeners are generally too tardy in the destruction of these creatures ; 

 the instant they appear they should be killed with tobacco smoke. 

 Melon and cucumber plants frequently perish from the attacks of 

 these creatures, as they remain unnoticed on the under surface of the 

 leaves. 



The aphis exists in three states, the larva, the pupa, and the winged 

 or perfect insect. It multiplies with extreme rapidity, and in the 

 winged state frequently appears in vast clouds, filling the air and 

 settling upon every object. Eggs are laid at the end of the year by 

 some species, and I have hatched eggs experimentally in warm houses, 

 to be sure that they were the eggs of aphides. It is a remarkable fact 



