848 Journal of Agricultural Research vol. vi, No. 22 



abundant in some sections as Sigalphus curculionis Fitch. Thereafter 

 until 1906 there were published apparently only two references to the 

 species; one by Riley and Howard (5), which is a repetition of the 

 original breeding record, and one by Harrington (6, p. 67), in which the 

 insect is merely mentioned as a parasite of the plum curculio. In 1906 

 Johnson and Girault (7, p. 6) mentioned this insect in the account of 

 their work on the plum curculio in New York, and accorded it small 

 importance in the control of its host. Quaintance and Jenne (8, p. 

 147-148) in 1 91 2 gave a resume of previously published accounts, to- 

 gether with data on the abundance and emergence of adults in spring 

 in New York and Pennsylvania. As showing the distribution of the 

 species these authors list the following States : New York, New Jersey, 

 Connecticut, Illinois, Missouri, and Kansas. 



HOSTS AND DISTRIBUTION 



So far as is known the plum curculio is the only insect attacked by 

 this species, published records showing it to have been reared from this 

 host in Connecticut, New York, New Jersey, Pennsylvania, Illinois, 

 Missouri, and Kansas. In addition to these States the writer has had 

 material from Michigan. 



LIFE HISTORY OF THE SPECIES 



GENERATIONS 



This species is single-brooded, the life cycle of one generation embracing 

 the whole year. The adult stage is reached in the fall, but the perfect 

 insect does not leave its cocoon until the following spring. 



EMERGENCE OF ADULTS 



The adult T. conotracheli emerges from its cocoon from late May to the 

 middle of June and very shortly begins the search for hosts. 



RELATIVE ABUNDANCE AND TIME OF EMERGENCE OF SEXES 



The males begin to appear a few days ahead of the females, and the 

 latter continue to emerge long after the last male. A lot of cocoons 

 collected by the late A. G. Hammar at Douglas, Mich., in the spring of 

 191 1 and reared by the writer at Vienna, Va., produced adults as indi- 

 cated in Table I. This table shows the date and period of emergence, 

 the comparative dates of emergence of males and females, and the pro- 

 portion of the sexes. 



