NATURAL ENEMIES. 



37 



elevations and bring these into the laboratory, thus supplying them 

 artificially. There were 230 individuals liberated in field cages, the 

 coverings of which were later removed, and 49 liberated directly 



Fig. 19.— Pteromalid parasite of larva and pupa of the alfalfa weevil: Adult female. Greatly enlarged. 



(Original.) 



Fig. 20.-Pteromalid parasite of larva and pupa of the alfalfa weevil: Adult male. Greatly enlarged. 



(Original.) 



into the open field. Observations have since shown that this species 

 has actually colonized itself in the field; whether temporarily or per- 

 manently it remains to be seen. 



