Insects. 1291 



shining in the older than in the younger individuals : the tubes are pale green, and 

 about one-fifth of the length of the body ; their tips are pale fuscous : the legs are pale 

 green, or sometimes white ; their tarsi are pale fuscous : the abdomen has a rim on 

 each side ; the ventral segments are transverse, distinct, and nearly equal in size. The 

 eyes of the young ones are deep brown. Psylla Urticae, Linn., occurs in abundance 

 with this Aphis on the nettle in February. The honey-tubes, being moveable, are often 

 twined in different directions, one pointing forward, the other backwards. The antennas 

 repose over the back when this insect is at rest, but when it begins to walk, they are 

 brought in advance of its head, and moved up and down alternately. Among the pur- 

 poses in the creative arrangements which are effected by some beings serving for the 

 prey and food of others, are the support of the carnivorous species, the organization of 

 matter into higher forms of life, and the control of the increase of the victims, whereby 

 their existence, as species, is prolonged. The removal of this check by giving un- 

 limited course to the multiplication of individuals would deprive them of the means of 

 subsistence, and thereby endanger their continuance. This may have been a means 

 whereby the extinction of groups was executed in former periods of time, when many 

 kinds seem to have passed away without any other assignable instrument for their re- 

 moval from the sphere of existence. Vegetation would soon be comparatively free from 

 the attacks of Aphides, for these insects must perish from over-production, if their 

 swarms were no longer destroyed by the changes of the weather, and also, but in a tri- 

 fling degree, if they should cease to be the nourishment of Coccinellae, Hemerobii, 

 Chrysopae, Syrphi, Acari, and of various aculeate and parasitic Hymenoptera. In the 

 higher as well as in the lower orders of life, and in the history of mankind, the excess of 

 every evil is accompanied by its remedy, and its cessation introduces a new and better 

 epoch. 



'* I thank thee, Heaven ! thou hast ordained it wisely, 



That still extremes bring their own cure. That point 



In misery, which makes the oppressed man 



Regardless of his own life, makes him too 



Lord of the oppressor's. Knew I a hundred men 



Despairing, but not palsied by despair, 



This arm should shake the kingdoms of the world ; 



The deep foundations of iniquity 



Should sink away, earth groaning from beneath them ; 



The strong holds of the cruel men should fall, 



Their temples and their mountainous towers should fall ; 



'Till desolation seemed a beautiful thing, 



And all that were and had the spirit of life, 



Sang a new song to her who had gone forth, 



Conquering and still to conquer ! " 



5. Poa, Linn. Meadow Grass. 



Species infested. P. trivialis, Linn. Common meadow grass. 



Aphis radicum, Kirby and Spence, Intr. Ent. ii. 90. 



This species, which belongs to the genus Rhizobius of Burmeister, is common at the 

 roots of grass in January ; it is surrounded by white cottony matter which exudes from 



