107 



In auother vial I was delighted to flud an adult parasite, the cocoon 

 from which it had emerged, and the remains of the spider which had 

 supported it. Concerning this specimen, Mr. Emerton had made the 

 following note : 



Fly raised from larva on young Dictyna volupis Keys. The remains of the spider 

 and the pupa cocoon are in the vial. When found, May 15, 1887, the larva was about 

 half as long as the spider's abdomen and about ouefourth as thick. It was attached 

 by the mouth on the front of the abdomen. By May 18 the spider had died and the 

 larva was full grown, larger than the spider had been, and had begun to spin a cocoon. 

 May 25 it changed to pupa and the fly came out June 1. 



The adult parasite is a beautiful little Polysphincta S , and differs from 

 other described !North American species. 



Polysphincta dictynee n. sp. 



Male. — Length, 2.5""". Face obscurely carinate below insertion of antennae ; me- 

 sonotum shiniug, but with sliort, fine, and close pubescence ; metascutum with two 

 submediau longitudinal cariuje extending parallel to the nucha when they diverge; 

 nucha smooth, circular, rest of metascutum faintly shagreened. First abdominal 

 segment with a well-marked smooth central longitudinal dorsal groove, sides of groove 

 concave ; venter of abdomen strongly concave ; wiug veins all light brown ; no trace 

 of an areolet. Color : Vertex and occiput black, face lemon yellow ; autennal scape, 

 pedicel, and joints 1 and 2 of funicle yellow, rest of funicle brown ; mesothorax yel- 

 low with a large brown spot at front of scutum and one on each of the parapsides, 

 also one just anterior to scuto-scutellar furrow ; metathorax black; all legs yellow; 

 abdomen honey-yellow below, segments 1, 6, and 7 brown above, remaining segments 

 yellow, each with a definitely limited brown patch which is diamond-shaped on joint 

 2 and triangular on 3, 4, and 5. 



1 <? , from Dictyna volupis ; J. H. Emerton, Cambridge, Mass. 



The figures illustrating this note have been drawn by Miss Sullivan 

 from the material received from Mr. Emerton. Fig. 21, a, represents 

 the adult Polysphincta clictymv, and Fig. 21, 6, an outline drawing of 

 Linyphia communis with a i^arasitic larva in situ. The larva figured is 

 full grown and is quite apt to be that of the Polysphincta. No attempt 

 has been made in this sketch to show more than the position which the 

 parasitic larva assumes on the spider. 



REMARKS ON THE HESSIAN FLY.* 



At the meeting of the American Philosophical Society, May 4, the 

 anthor called attention to some grave errors in the published minutes 

 of the earlier meetings of the society. The public, as well as the most 

 competent authors, had always believed that the Hessian Fly was in- 

 troduced during the Eevolutiou by Hessian troops. Dr. H. A. Hagen, 

 of Cambridge, has argued against this belief. He has argued, further, 

 that the species was not imported from Europe. Professor Riley 

 showed that most of Hagen's arguments were weak and fell to the 



'Abstract of a paper by C. V. Riley before the Society for the Promotion of Agri- 

 cultural Science, Cleveland, Ohio, August 21, 1888. 

 8274 2 



