VITIS, VAIi. 



the drops of secretion produced between 6 p.m. and 

 <> a.m., (hiring Avhich hours I was unable to get ;mv 

 satisfactory results, as the drops of secretion invariably 

 coalesced during the night ; but if we allow for the 

 night about half the quantity secreted during the day, 







** ,ii(/W** 



FIG. 2. Pulvinaria ribesise, Sign. Illustrating secretion of honey-dew by 

 adult females : a, section of wall ; b, branch with insects ; c, paper 

 placed beneath branch to intercept and hold falling fluid. The dots on 

 c represent the distances to which the honey-dew was projected. All 

 actual size. 



FIG. 3. Pulvinaria ribesix, Sign. Diagram illustrating secretion of honey- 

 dew by adult females : a, section of wall ; b, insects ; c, paper placed be- 

 neath branch to intercept and hold the falling fluid ; d, section of branch. 

 The curved dotted lines indicate the probable course taken by the fluid. 

 The dots upon the paper indicate the actual size of each single drop of 

 the fluid and the position to which it was ejected. Section of branch, 

 and paper, actual size. 



we have an aggregate in round figures of 1200 drops 

 of secretion per day. Basing this calculation upon the 

 supposition that each of the 100 coccids elaborated the 

 same amount for a period of twenty-one days, which 

 in my experience is approximately correct, then 100- 



