WINE-MAKING IN CALIFORNIA. 51 



OBSERVATIONS IN THE LABORATORY, FROM 1881-1885. 

 For the better verification of the facts observed in the field, 

 and especially for the observation of the habits of the insects 

 during propagation, a series of laboratory experiments was 

 carried on simultaneously with the field observations. 



Conservation of Root Specimens. The first difficulty met 

 with was to preserve the root specimen, in such a shape that 

 it would not mould, and yet remain sufficiently moist to 

 afford sustenance to the insects. This is best accomplished 

 by placing a piece of root containing the required number of 

 insects into a wide-mouthed bottle, supplied with a close-fit- 

 ting cork. If it becomes necessary to remove the cork very 

 often, a few drops of water may be dropped into the bottom 

 of the bottle to supply any lost moisture, and then, by 

 regulating the temperature, the water can be vaporized and 

 condensed so as to reach all parts of the root. Some speci- 

 mens were kept in the sunlight, with a good circulation of air 

 through the bottle, but the insect did not thrive under this 

 treatment. Roots thus treated are more difficult to keep in 

 good condition, and the insect becomes more restless. A 

 cool dark place seems best fitted for these experiments. 



The leading questions studied were : 



1. Number of eggs laid by each mother louse. 



2. Rate of laying. 



3. Time required to hatch them into larvae. 



4. Time from the hatching of larvae to the egg-laying age. 



5. Pupa form. 



6. Winged form. 



Number of Eggs Laid. Two or three specimens contain- 

 ing isolated mothers were placed in bottles and observed 

 every few days. The highest number of eggs from any of 

 these insects was about seventy-five. Numerous bottled roots 

 have specimens of sixty to seventy eggs and larvae together. It 

 is not uncommon to see a nest of forty to fifty in a row, upon 



