POTATO SPRAYING AND DUSTING. 19 



but this is only of interest in so far as it gives one an indication merely of the value 

 of the insecticides. The conditions were too unnatural to allow of the experiments 

 being a real test. 



A Hymenopterous Parasite of the Flea-Beetle. 



Throughout the summer, from the middle of July until the beginning of September, 

 when a period of rather low temperature was experienced, driving the flea-beetle 

 into hibernating quarters, a small species of Braconid was often observed in close 

 association with it on the potatoes. Specimens sent to Dr. L. 0. Howard, Chief of 

 the Bureau of Entomology, Washington, D.C., were transmitted to Mr. J. C. Crawford 

 of the National Museum, who kindly identified them as Perilitus epitricis, Viereck. 

 As it so happened, the occurrence of this species in New Jersey proved interesting, 

 as being a new record for this State. 



The following observations were made on 30th July. As the flea-beetle moves 

 over the leaf surface, the Hymenopteron follows closely in the rear with its two 

 antennae outstretched, one on each side of its prey. Whenever the latter stops, 

 the Braconid follows suit and remains often perfectly motionless. Sometimes, 

 however, it becomes quite excited and rapidly encircles its host in a curious, terpsi- 

 chorean fashion. When about to attack, the Hymenopteron orients itself, either 

 anteriorly or posteriorly, in a direct line with the flea-beetle and artfully recurving 

 its abdomen downwards and forwards, strikes it in the vulnerable places of its armour, 

 the intersegmental parts of the abdomen. Thus the act of oviposition is completed, 

 but apparently not always successfully, for the aggressive action may be repeated 

 several times in the same host by the same parasite. From various specimens of 

 flea-beetles collected during the summer and maintained in captivity, this parasite 

 was reared. The point of emergence is a hole usually found in the anal region of the 

 parasitised beetle. 



In conclusion I wish to express my warmest thanks to Dr. T. J. Headlee, State 

 Entomologist, who during my sojourn in the United States gave me the greatest 

 assistance in carrying out this work, while he has always been ready with valuable 

 hints and suggestions as to the methods to be employed. My thanks, too, are 

 due to the Experiment Station authorities who made it possible to carry 

 through the experiments to completion. My only regret is that unforeseen and 

 unavoidable circumstances necessitated the rather hurried writing up of the results. 



Summary. 



In employing the most up-to-date methods in the prosecution of his business, the 

 American farmer endeavours to get the best return for his labours. The adoption 

 of the latest prophylactic measures for combating the fungus and insect enemies 

 of his crops, is but a single instance of that progressiveness which is characteristic 

 of the man. 



The State Agricultural Experiment Stations encourage the farmer in many ways 

 and are of genuine practical value in dealing with local problems. The establishment 

 of similar institutions in this country would be quite justifiable. 

 (C155) b2 



