Oct. 23, 1916 
Life History of Habrocytus Medicaginis 
153 
removed with its host from an alfalfa seed collected on December 19, 
1913, transformed to the pupal stage in May, 1915, and emerged as an 
adult on June 2, 1915. On the other hand, a newly hatched larva of 
this species was placed upon its host on April 22, entered the pupal stage 
on May 5, and emerged as an adult on May 19. Another newly hatched 
larva placed under observation on September 5 had developed, pupated, 
and emerged as an adult by September 24. Infested alfalfa seeds which 
were collected on October 1, 1912, showed an adult of H. medicaginis 
emerging as late as April 9, 1914. These observations show that a period 
of from about 30 days to 1 year, and almost 2 years in exceptional cases, 
may be required for the completion of a single generation. 
HIBERNATION 
H . medicaginis hibernates in the larval stage within the infested alfalfa 
seeds which remain on the standing alfalfa, or on the ground when winter 
approaches. The undeveloped larvae and those still in the pupal stage 
are usually killed by the first severe frost. In the mild climate of southern 
California occasional individuals of this species hibernate in the pupal 
stage. Nearly 100 larvae of H . medicaginis were removed from their 
natural inclosure within the alfalfa seeds and placed in cavities between 
two layers of sheet cork. Of these larvae 74 lived throughout the winter, 
entering the pupal stage in the months of March, April, and May at 
Glendale, Cal. 
RATE OF PARASITISM 
While this species is generally distributed throughout the alfalfa seed¬ 
growing districts of the United States, the rate of parasitism is not so 
large as might be expected. The comparative rearings of H . medicaginis 
and their host (B. funebris) show parasitism by H. medicaginis in several 
localities to be about as follows: Corcoran, Cal., 0.8 per cent; Tulare, 
Cal., 2.8 per cent; Chino, Cal., 2.8 per cent; and Yuma, Ariz., 4.9 per 
cent. 
