OBSERVATIONS ON THE LIFE HISTORY OF 

 PTERODONTIA FLAVIPES GRAY. (DIPTERA.)* 



By J. L. King, Wooster, Ohio. 

 INTRODUCTION. 



During the summer of 1915, while at Gypsum in northern 

 Ohio, the writer found several pecuHar dipterous larvae under 

 burlap bands which had been placed around the trunks of some 

 apple trees. The adults reared from these proved to belong to 

 the genus Pterodontia of the family Cyrtidse. From^ the 

 literature at hand it was evident that little had been published 

 concerning the habits of this interesting family. This stimu- 

 lated further observation, the results of which are recorded in 

 this paper. Later a more thorough study of the literature was 

 made, particularly of those articles which deal with the life 

 histories of the members of the family. These have been 

 briefly summarized and are appended after each special topic. 



The writer wishes to express his gratitude to Professor A. D. 

 MacGillivray for his kind interest and help in the preparation 

 of this paper. Thanks are also due to Mr. J. R. Malloch, of the 

 Illinois State Laboratory of Natural History for the identifi- 

 cation of the species, and to Mr. Nathan Banks for the 

 determination of the host spiders. 



THE MATURE LARVA OF PTERODONTIA. 



On July 20, 1915, three larvae were found under the burlap 

 bands which surrounded the trunks of some large apple trees. 

 In all cases the larvae were found either suspended in abandoned 

 spider webs or entangled by threads and resting partly on the 

 bark or on the burlap. When suspended, their position was 

 maintained by the web adhering to their sticky body surface. 

 In two cases the remains of spiders were found near the larvae. 

 The largest larva, measuring 8 mm. in length, had emerged 

 from the abdomen of an Epeirid spider, Epeira sericata Clerk, 

 leaving the abdomen through a comparatively small hole on 

 the ventral side, in the region of the anterior lung-sHt. From 



*Contribution from the Entomological Laboratories of the University of 

 Illinois. No. 49, and the Ohio Experiment Station, Wooster, Ohio. 



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