I^ATUEAL EXEMIES. 
37 
elevations and bring these into the laboratory, thus supplying them 
artificially. There were 230 individuals liberated in field cages, the 
coverings of wliich were later removed, and 49 hberated directly 
Fig. 19.— Pteronialid 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 sho^\Ti that this species 
has actually colonized itself in the field; whether temporarily or per- 
manently it remains to be seen. 
