54 INJURIOUS INSECTS. 



most perfect of all the Parenchymatous Entozoa ; they are called Acan- 

 thocephala. These animals, although they resemble the preceding genera 

 of the family in their digestive apparatus, having no outlet except the mouth 

 for discharging the residue of digestion, yet, in the organs of reproduction, 

 they are infinitely superior, "and present a manifest analogy with higher 

 classes, indicated by the complete separation of the sexes." They are 

 Entozoic in their habits, and their mouths are armed with sharp recurved 

 hooks, which enable them to hold securely to that part to which they 

 are affixed. 



Uppingham, January 1th., 1857. 



INJURIOUS INSECTS.— No. VII. 



APHIS, (APHIDI1, L.,) OR PLANT-LICE. 



BY J. Mc'lNTOSH, ESQ. 

 C Continued from page 181, Vol. 6.) 



Aphides. — Each of these" unwelcome visitants to our plants seems to live 

 only to eat and be eaten; they take no trouble to conceal themselves, or 

 even to shelter their bodies from the passing inclemency of the weather; sun- 

 shine or storm are alike to them; and while the emptied carcases of their 

 neighbours are being piled around them in heaps by their enemies, they 

 go on sucking the juices from the tender shoots and leaves, and as long 

 as there remains a drop of sap on which they chance to be, they stick to 

 their position until their time has come to be sucked by the larvae of 

 the beautiful Hemerobius, L., Syrphice, and the interesting Coccinella, of 

 Linn. 



The injuries occasioned to plants by these insects are greater than would 

 at first sight appear from their small size and apparent weakness, but they 

 make up in number what they want in strength, and thus become such 

 formidable enemies to vegetation. Plants are differently affected by them; 

 some wither and cease to grow, the leaves and plants put on a sickly 

 appearance, and some die from exhaustion; others, although not killed, are 

 greatly impeded in their growth, and the tender parts which have been 

 attacked become stunted. Their punctures seem to poison some plants, 

 and affect others in a most singular manner, producing warts or swellings, 

 some of which are solid, and some hollow, containing thousands of the 

 descendants of a single individual, whose puncture was the original cause 

 of the tumour. The diseases caused to vegetation by these all-destroying 

 pests, are worthy of being inquired into, and worthy of man's power to 

 remedy; but unfortunately some of them are not to be remedied, at least 



