THE society's NOTE-BOOKS. 303 



Ticks.— Nicholson is quite correct in placing Ticks among the 

 Acarina, of which order they constitute a considerable family, 

 under the title IxodidcB, which includes Argus also. The Sheep- 

 tick (so called) is not a tick at all, but a degraded fly. It has only 

 six legs, in common with other insects, whereas the Ticks and 

 remaining families of the Acarina have all eight legs, barring 

 certain degraded forms. I think, however, the main point of dif- 

 ference between the different families have been more than once 

 pointed out in our Note-books by myself, and it seems superfluous 

 to repeat these matters with each fresh box. 



I am afraid I cannot enlighten Mr. Ingram more definitely as 

 to the functions of the Acari that avail themselves of the shelter 

 of the nests of ants, beyond stating that they are probably induced 

 to remain there because of the food picked up amongst their hosts. 

 Again, they probably act as scavengers ; but I feel doubtful as to 

 whether any more intimate connection exists, or that they are 

 there on any other principle than that of toleration. It is true, 

 however, that they are not found indiscriminately in a// ants' nests, 

 and.that certain Acari appear to be associated with certain kinds 

 of ants. 



The thanks of the Society are due to Miss F. Phillips for her 

 nicely-executed drawings. E. Bostock. 



EXPLANATION OF PLATES X. and XI. 

 Plate X. 

 Fig. 1, 1. — Uropoda formicarice, $ and 5 • 

 ,, 2. — TJ. canestriniana, 5, x 50. 

 ,, 3. — U. cocdnea, 9 , ^ 50. 

 ,, 4. "1 l/". (? sp.), (J, from nests of F. flava. 



5. ]u. (?sp.), c?, ditto. 



,, 6. — Zeterchestes micronychus, x 50. 



Plate XI. 

 ,, 7. — Uropoda laminosa (? sp.), ^j ^ 50. 

 ,, 8.— Lcelapn Ictvis, (J, x 50. 

 ,, 9. — L. cunifer, (J, x 50. 



,, 10. — L. equitans, x 50. 



„ ll.-i. - (? sp.). 



„ 12.-i. - sp.)- 



