6 Transactions of the 



common on house-flies ; and the specimens which have been shown 

 me in illustration of the fact are identical with that kindly sent for 

 exhibition by ]\Ir, Tatem on Nov. 5. So that the species which I 

 have alluded to in my paper as A. Musese, and which I at first 

 thought was the same as Mr. Tatem 's, must receive another name ; 

 but the task of giving it a name I leave to some one better qualified 

 than myself. As I have stated in the paper, I first found it on an 

 Obisium, and afterwards on Gamasi, and have strong reason for 

 thinking the early stages of those now in my possession were passed 

 in my cells in the character of a vegetable-feeding mite of very 

 unprepossessing habits and exterior. Although in the three ex- 

 amples of this genus of the minute Arachnida recorded in Mr. 

 Tatem 's paper and mine, I am sure that the four-legged theory is a 

 mistake, I am not in a position to say the theory may not hold good 

 in the case of other mites which I have not met with. It is neces- 

 sary I should clearly explain myself on this point, as it appears 

 from conversation with certain Fellows of the Society, who heard 

 the paper read, that I have left it doubtful whether I have not 

 been trying to upset well-authenticated facts in regard to the im- 

 perfect development of the legs in the Arthropoda, a position which 

 I have not the least intention to assume. I have just succeeded in 

 mounting the mite in question in balsam, and, as I expected from 

 analogy, the hind legs quite vanish from view unless they happen 

 to take a position in which they can be seen clear of the creature's 

 body. 



S. J. McIntire. 



