278 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 2 



A PARASITE ON THE ASPARAGUS BEETLE 



By H. T. Fernald, Amherst, Mass. 



The unfortunate freedom of the asparagus beetle (Crioceris as- 

 paragi L.) from parasites in this country has often been remarked. 

 It was with much interest therefore, that on June 2 of the present 

 year the writer observed several tiny Chalcids running about on as- 

 paragus stalks, and after a few minutes observed one ovipositing in 

 the egg of an asparagus beetle. Several of the parasites were cap- 

 tured and a specimen was sent to the Department of Agriculture at 

 Washington where through the kindness of Dr. Howard and Mr. J. 

 C. Crawford it was determined as belonging to the genus Tetrastichus, 

 but in too poor condition for specific location. 



The parasites are very small, measuring from two to a little less 

 than three millimeters in length, and when seen in the sunlight as 

 they move about are brilliant metallic green in color, particularly 

 on the abdomen. 



Their actions on the plant were carefully studied and gave the 

 impression of stupidity on the part of the insects, for though plainly 

 searching for beetle eggs they would frequently pass within two or 

 three millimeters of them without being apparently aware of the 

 fact. They would travel up and down the main stems and branches, 

 rarely pausing, though giving no appearance of haste, often cover- 

 ing the same ground several times and examining eggs they had al- 

 ready looked over, as though entirely unaware that this was the 

 case. They were not easily disturbed and could be closely watched 

 with a pocket lens, the shadow caused by the head and hands of the 

 watcher having no effect. 



Apparently about one egg in every eight or ten examined proved 

 acceptable, and the parasite after a short period (for consideration?) 

 moved out on the egg which was long enough to permit it to support 

 the parasite. The insect then slowly bent its abdomen and inserted 

 its ovipositor in the egg where it remained for five or ten seconds, 

 after which it was withdrawn and the parasite resumed its travels. 



A number of eggs were seen to be punctured in this way and the 

 parasites were by no means difficult to find for about a week. Later 

 they disappeared, or at least none were captured till July 12, when 

 one was captured, and others were found the following day. 



At the time of the first discovery of the parasites, the asparagus 

 beetles were abundant and eggs were extremely so. During the fol- 

 lowing month the weather was favorable for the development of these 



