62 ANIMAL PARASITES. 



potatoe very nimbly. Martius has figured it, but I have 

 given an illustration from one which I captured myself. 

 There is no reason whatever for believing that it causes 

 the malady. Mr. Ingall, who was so kind as to make the 

 drawing, remarks that this little fellow, when viewed under 

 the microscope travelling among the dense growth of the 

 fungi, put him in mind of a great rhinoceros trotting about 

 in the jungles. He certainly does present a very extraor- 

 dinary appearance. (Plate vn.) 



(246.) There is a little yellow insect which is common 

 upon all potatoes, but I do not know its name. It appears, 

 however, to me to be quite innocuous, for I have found it 

 upon other vegetables which have been quite healthy and 

 uninjured. In the " Gardener's Chronicle" two insects 

 are figured which have been supposed to have an influence 

 on the disease the potatoe thrip and the Eupteryx solanij 

 but I see no evidence to suppose that they cause the 

 malady. 



(247.) Lady-birds of different species are to be met with 

 in great profusion on the potatoe and other plants, but they 

 are animal feeders, and can therefore do no harm. Various 

 ichneumons also in great numbers are to be found, together 

 with many dipterous insects, to neither of which can any 

 hurtful quality be assigned. 



(248.) If, however, we carefully examine the potatoe at 

 different times, we find another insect, an Aphis, in great 

 abundance ; which Aphis exerts so important an influence, 

 that I must devote to it an entire chapter, in order to sepa- 

 rate it from other animal parasites, and treat it with that 

 respect which its formidable powers unfortunately entitle 

 it to. On one occasion I found a second Aphis, of a black 

 color, on the plant, different from the one just mentioned, 



