234 



MR. A. M. ALTSON ON THE LIFE-HISTORY AND 



20 larvae. The remainder, five, were returned to their dish, and 

 the female placed in a tube. The surface of soil was on this date 

 quite dry. 



On 14th January the contents of the box were examined, but 

 in removing the first inch strip of the "side," some of the dry 

 soil fell out and the dead larva with it (this is recorded as g" 

 in the table); greater care was then exercised in removing the 

 other strips. The result is shown for convenience in Table lY. 



Table IY.— Depth of Soil penetrated by parasitized larvae. 



Depths 



1 " 



1 " 

 2 



1" 



H" 



li" If" 



2" 



2i" 



2k" 



9ii" 

 -4 



3" 



Totals. 



Lavvffi 













3t - 



1 



2 









7 



Puparia 







1 



1 



3 4 



6 



7 



10 



3 



4 



39 



Totals 





1 



1 



1 



6 4 





9 



10 



3 



4 



46 



* Dead. f 1 dead. 



When removing the soil, which was done by gradually scraping- 

 it off with the edge of a steel rule, it was found that at 2| inches 

 down the soil was caked and still damp. This coagulation was 

 no doubt due to running the water into the box on very dry soil. 

 Seven of the puparia were broken in scraping the soil ofi". 



Ex'peri'meiit No. 4. — Another experiment of the above descrip- 

 tion was carried out, but in this instance the soil was spread out 

 into a tray and damped before putting it into the box. The 

 same wooden box was used, and filled with this soil to a depth 

 of 7 inches. The experiment was started in the morning of 

 22nd January, 1920. Pieces of liver were placed on the soil, 

 and one female ^-1. mandacator allowed to emerge from a tube on 

 to it ; 25 larvae were then given separately for oviposition. The 

 female effectively dealt with these in 45 minutes ; she was then 

 removed and another female taken from the cage. The second 

 female was also given 25 larva', and disposed of these in an hour 

 and a quarter. Over-parasitization was observed to take place 

 in one larva in this experiment. 



On 27th January, 1920, five days later, the contents of the box 

 were examined by the same process of scraping the soil off; it 

 had not coagulated in this case, and only two puparia were broken. 

 The result of the experiment is given in Table Y. 



Table Y. shows that 19 larvae went deeper than any in No. 3 

 experiment, there being an absence of caked soil. 



Both experiments Nos. 3 and 4 showed that the majority of 

 Braconid parasitized larvae reached 2 inches or more under the 

 surface of the soil. 



Three experiments were made to ascertain the burrowing 

 capacity of hrevicornis. Nos. 5 and 6 were staited before the 



