16 



ENTOMOLOGICAL SOCIETY 



adults varied from 3 to 12 or possibly more. Doctor Howard 

 has called attention to the position of these parasites, heading, 

 as may be seen in the illustration, toward the nearest end of 



the pupa case. This rule has some ex- 

 ceptions, but seems to hold good in the 

 majority of those examined. Many of 

 these Polygnotus were living when these 

 mounts were made, but those that re- 

 mained in the straw all died before 

 New Year's, possibly because of lack of 

 moisture or on account of abnormal con- 

 ditions generally. 



Figure I illustrates a most unique ex- 

 ample of hyperparasitism of the Hessian 

 fly discovered in one of these mounts 

 after they had cleared. Two perfect 

 adult Polygnotus are to be seen within 

 the pupa case, while beside them, lying 

 in what is clearly a Polygnotus cell, is an 

 adult Tetrastichus. The cells occupied 

 by the Polygnotus are clear and free 

 from debris, exhibiting only the black 

 residue of matter remaining from the 

 larval state. In the other cell with its 

 strange guest, besides the same black 

 residuum is a mass of debris or floccu- 

 lent matter, extremely suggestive of a 

 previous tenant. 

 It is of course impossible to determine the species of this 

 Tetrastichus nor can it be known if it was introduced with the 

 Polygnotus from Pennsylvania, or if it made the attack from 

 ground already occupied by it. In any event it plainly oper- 

 ates to the disadvantage of the farmer by lessening the army 

 of Polygnotus, thus befriending the Hessian fly. 



FIG. 2. Adults of 

 Polygnotus which have 

 developed within the 

 " flaxseed," or puparium 

 of the Hessian fly, 

 Mayetiola destructor. 

 (Drawing made in the 

 Bureau of Entomology 

 and published by permis- 

 sion of the Secretary of 

 Agriculture.) 



NOTE ON THE OCCURRENCE OF CAMPYLOMYZA. 

 SCUTELLATA SAY. 



[Diptera, Cecidomyiidae.] 

 By C. N. AlNSLlE. 



I desire to record the discovery of a new habitat of a hitherto 

 rare dipteron, Campylomyza scutellata. 



While at Jefferson, Ohio, October 10, 1907, my attention was 



