NATURAL ENEMIES. 



39 



alfalfa weevil the possibility of permanent establishment and future 

 efficiency in the case of these species seems rather more encourag- 

 ing than in case of the others. During June, 1911, 40 individuals 

 reared from imported cocoons were placed in field cages artificially 

 overstocked with weevil larvae, the cage covers being removed later. 

 Besides this, there is at present on hand a considerable amount of 

 hibernating material (PL XII, figs. 1, 2) artificially reared in the 

 Murray laboratory (PL XIII, fig. 2), which will be allowed to escape, 

 naturally, into the alfalfa fields. 



Fig. 25. — Canidiella curculionis, a parasite of the alfalfa weevil: Adult female; lateral view of abdomen 



of same below, at right. Enlarged. (Original.) 



The parasite Itoplectis masculator Fab. (fig. 26) differs from the 

 preceding by reason of the fact that it pupates entirely within the 

 pupa of its host. It is known to be a primary parasite, but the num- 

 ber so far secured is too limited to warrant any discussion regarding 

 it, or any predictions as to its future in America. 



Of the eighth and last of these parasites, Hemiteles sp., very little 

 is known either in Europe or America, and with the obscurity surround- 

 ing its habits it may prove to be either a primary or secondary 

 parasite, a friend or an enemy of the others. It is therefore being 

 handled with the utmost caution, none having been liberated either 

 in the fields or in field cases. 



