32 



BULLETIN 1218, U. S. DEPARTMENT OF AGRICULTURE. 



of T. phaenops deposited August 3 was placed in a vial containing 

 some hatched egg masses of T. punctifer on which were freshly- 

 emerged parasites. On August 9 the egg mass of T. phaenops was 

 again isolated and from it on August 12 hatched 186 Tabanus 

 larvae. On August 27 one of the unhatched eggs was opened and 

 a pupa of a parasite was found. Several adults of the parasites 

 emerged August 29. Thus while eggs of T. phaenops are not known 

 to be infested with any parasite in nature, this parasite was success- 

 fully reared from it in captivity. 



Transportation of Parasites. 



This same parasite, Prophanurus emersoni, was previously reared 

 by D. C. Parman at Uvalde, Tex., from egg masses of Tabanus 

 hyalinipennis Hine. On account of its abundance and the abun- 

 dance of the host eggs in that locality in Texas, it was considered 

 wise to attempt the transportation of the species from Texas to 



Nevada and Cali- 

 f o r n i a . A few 

 masses of infested 

 eggs were mailed 

 from Uvalde, Tex., 

 on June 25. On July 

 2, a*t Topaz, Calif., 

 these masses from 

 which parasites were 

 already emerging 

 were placed in a vial 

 with an egg mass of 

 T. phaenops depos- 

 ited July 1. On July 

 6 the eggs of T. phae- 

 nops seemed to be 

 somewhat shrunken. 

 On July 8 the egg 

 mass was isolated. On July 22 some of the eggs of T. phaenops 

 had hatched. On September 16 five parasites had emerged and 

 were found dead in the vial. The antenna? of another dead one 

 were protruding through an emergence hole in the leaf to which the 

 mass was attached. 



There can be little doubt that the activity of Prophanurus emer- 

 soni is a very important factor in the control of Tabanus punctifer. 



PREDATORS. 



Bembex primaaestate Johnson & Eohwer (fig. 17) is an insect 

 similar to the " horse guard," Monedula Carolina Drury. Hine (4) 

 has given an account of the habits of the latter in Louisiana, and 

 believes it to be an important enemy of horse-flies. 



Residents in Antelope Valley had frequently observed the capture 

 of horse-flies by wasps. In September, 1916, the senior author ob- 

 served one pursuing a tabanid. A few minutes later one of these 

 wasps was captured. It was identified as Bembex primaaestate'. On 

 July 19, 1917, a nest of this species was found in sandy gravel. 



Fig. 17. — Bembex primaaestate, a predator upon horse-flies. 



