Mr. J. Hardy on Excrescences from Mites. Ill 



recollection, I have endeavoured to draw out the frail record. It 

 is a melancholy reflection, albeit a common one, that thus, in the 

 lapse of years, shall pass away the vestiges and the memories of 

 those who have come behind them ; and that another race, un- 

 conscious of the past, will, with like irreverence, tread upon their 

 ashes and deface their proudest devices. Is it in reference to 

 such futile attempts to become renowned, that the philosophic 

 Roman historian drops a comment on the tomb of Otho ? — " A 

 sepulchre was raised to the memory of Otho, but of an ordi- 

 nary structure, protected by its meanness, aad therefore likely 

 to last!''* 



On some Excrescences, 8^c. on Plants occasioned or inhabited 

 by Mites. By Mr. James Hardy. 



A FEW days ago, I met with several small galls on the leaves of 

 the hackberry (Prunus Padus), which I expected would furnish 

 the larva of a gall-midge {Cecidomyia) or gall-fly (Cynips). They 

 are green or slightly purplish, obovate, thickish, white, hirsute, 

 and are scattered over the upper surface of the leaf, like a crop of 

 minute mushrooms. On opening them I found them hollow, 

 without any apparent inmate, nor anything remarkable except a 

 few hairs, the continuation apparently of a thick crop placed at 

 their orifice in the depression on the underside of the leaf. A 

 few pink objects, however, at length caught my attention ; and 

 on reflection, knowing that such excrescences were sometimes 

 ascribed to mites, I resolved to ascertain if these were not such. 

 Next day, on shaking a few upon a slip of glass, and placing 

 them under the microscope, I observed that they exhibited motion; 

 and some of them were not long in pushing out their legs and 

 crawling slowly about. They were all in the larva state, are 

 elliptical, round-bodied, have four short legs placed close behind 

 the head ; the abdominal part is long and flexible and has about 

 four hairs before the tip, and about as many near the shoulders. 

 They are too minute to be seen with the naked eye ; even under 

 a triple lens they are mere lineai* atoms, without vestige of 

 limbs. They are white, yellow, pale brown, or pinkish. Two 

 species of mites were found on the outside; one a yellowish, rapid 

 running species, common upon foliage, that appears to deposit 

 its ova upon the hairs of the plants on which it occurs; the 

 other was a true, flattish, pale whitish testaceous Acarus, and is 

 most likely the parent of the young mites in the gall. 



Knowing there were many similar galls on leaves, I next in- 

 vestigated those hairy purple warts so abundant near the midrib 



* " Othoni sepulchrum exstmctum est, modicum, et mansurum."* — 

 Tacit. Hist. ii. c. 49. 



