500 ENTOMOLOGICAL SOCIETY 



Another trip was again made to the same locality on the 2yth 

 of September. But very few of the ants were observed, while 

 the flies were still more scarce. Only one female was captured, 

 which was still alive and very active the next morning. On 

 placing one of the ants in the tube containing the fly, I soon ob 

 served that the ant had become aware of the presence of its enemy 

 and commenced to run restlessly back and forth, the fly watching 

 it rather interestedly ; coming accidentally in contact with the 

 fly, the latter darted at the ant, which, enraged at this unsus 

 pected attack, went for it with a furious rush and widely open 

 mandibles. For a moment there was a general mix-up, remind 

 ing one strongly of two tom-cats in a fight, during which combat 

 the ant was trying hard to catch the fly with its legs and mandi 

 bles, though on -account of its extreme agility it rushed between 

 the legs of the ant and escaped unharmed. This battle was kept 

 up for some time, the fly jumping on the back and head of the 

 angry ant till both became tired out, especially the ant, which 

 walked about slowly, cleaning her head, mouth, antennas and 

 legs ; the poor creature became at last so completely exhausted 

 that her legs commenced to tremble. The fight between the two 

 had evidently lasted through some part of the night, when the 

 ant at last succeeded in capturing the fly, which it crushed to a 

 shapeless mass. On examining the ant the next morning, I 

 failed to find any eggs on any part of its body. 



After rearing this fly I wrote to the distinguished European 

 writer on Formicidas, Professor Charles Emery, and asked him 

 whether he knew of any observations upon the decapitation of 

 ants. He replied that nothing of this nature had been called to 

 his attention, except the fact that Formica exsecta, a very savage 

 fighter, in the course of its battles frequently cuts off the heads of 

 its opponents. 



Later, mentioning the matter to Dr. L. O. Howard, he called 

 my attention to the observations reported by Dr. W. H. Fox, at 

 the September, 1887, meeting of this society, published in Vol 

 ume I, pp. 100 and 101. Dr. Fox found the decapitated heads of 

 Camponotus pennsylvan.icus at Hollis, New Hampshire, in the 

 summer of 1887, and discovered that they contained Dipterous 

 larvae. At a meeting of the Biological Society of Washington, 

 held in October, 1887, Dr. Howard mentioned this observation 

 of Dr. Fox's and suggested that the Dipterous larvae in question 

 might belong to the family Conopidae, the larvae of certain species 

 of which in Europe are parasitic upon Hymenopterous insects. 

 The present observations set the matter at rest and indicate the 

 true nature of the parasite. It is probably identical with or at 

 least congeneric with the species observed by Dr. Fox in New 

 Hampshire. The adult parasites were referred to Mr. Coquillett, 

 who finds that they constitute a new genus of the family Phoridse. 



