CLOVER AND ALFALFA SEED CHALCIS-FLY. 17 



PASTURING INFESTED FIELDS. 



The great mistake of pasturing alfalfa seed fields which have be- 

 come too severely infes^ted to yield a crop worth harvesting is too fre- 

 quently made. Live stock walking through the ripe alfalfa cause 

 the seeds to be shelled out and those infested with hibernating larva? 

 of the chalcis-fly fall on the ground, where they become the source 

 of infestation for the following year. 



HYMENOPTEROUS PARASITES. 



TETRASTICHUS BRUCHOPHAGI Gahan (6). 



Tetrastkhus hruchophagi'^ (PI. Ill) is generally distributed over 

 most of the northern half of the United States. In the central Cali- 

 fornia alfalfa seed-growing sections it is the most active of the pres- 

 ent known parasites of Bn'ucho'phagus fwnebris. While it can not be 

 depended upon to control the alfalfa-seed chalcis-fly, it has been ob- 

 served to destroy about 50 per cent of the larvae of the chalcis-fly 

 normally in the fields. This species develops within the seed and 

 feeds upon the larval stage of its host. 



LIODONTOMERUS SECUNDUS Gahan (8). 



LiodontOTTi&rus secvmdus ^ (PL IV) has been found by the writer 

 to be an active parasite upon the chalcis-fly when the latter infests 

 the seeds of red clover. It does not seem to attack the chalcis-fly 

 larvae infesting alfalfa seeds. This species is apparently most active 

 in the red-clover seed-growing sections of Oregon and Idaho. It is 

 active in the fields throughout the summer and hibernates in the lar- 

 val stage within the infested seeds left on the field. 



EUTELUS BRUCHOPHAGI Gahan (8). 



Eutelus hrucho'pJiagl" (PL V) is of economic importance as a 

 parasite of the chalcis-fly. in the mountain valleys of southern Idaho 

 and central Utah. It has also been found by the writer east of the 

 Sierra Nevada Mountains in northern California. It does not appear 

 to be present in the southwestern alfalfa seed-growing districts. 



LIODONTOMERUS PERPLEXUS Gahan (8). 



Liodontomerus perplexus- (PL VI) is a parasite of considerable 

 importance in checking the abundance of the chalcis-fly breeding in 

 alfalfa seeds throughout western Arizona. It was reared as far north 



1 For a more complete account of tJie species, see. Urbains (10). 



2 For a more complete account of this species, see Urbahns (11). 



