August — December 1SS9.I 



rS re HE. 



279 



Parasitism of Hippodamia convergens. 

 — On page 18S of the present volume of 

 Psyche is an article bv C. M. Weed and C. A. 

 Hart in which is recorded their observations 

 on the lady-beetle parasite {Perilihts ameri- 

 cafiHs), an account of which was first given by 

 Dr. C. V. Riley on page loi of volume t of 

 Insect life. All of the observations referred 

 to in these articles speak of this parasite 

 as attacking Megilla maculnta except in one 

 instance where Dr. Riley speaks of one spec- 

 imen of C. g-notata which was probably 

 attacked by the same parasite. I wish to 

 add H. convergens to the list, a single spec- 

 imen of which I took on the 17th of August, 

 1889, from a corn leaf where it was standing 

 dead, over a little brown cocoon exactly as 

 M. miicniata is represented in Insect life. 

 The parasite had escaped when the discov- 

 ery was made. 



This has been the most common lady- 

 beetle at Ames, Iowa, the past summer 

 wherever jilant lice have been abundant. 



. C. P. Gillette. 



Emphytus cinctus in America. — Late 

 in the autumn of 1887 I found a large num- 

 ber of sawfly larvae, not before observed, 

 on the under side of leaves of several species 

 of rose bushes at the Arnold Arboretum and 

 one or two otlier places in the vicinity of 

 Boston. Early in 1888 two or three sa\\flies 

 emerged from some larvae which had been 

 kept in confinement from the previous au- 

 tumn, but being forgotten little more than 

 the wings were found. The larvae were 

 again plentiful in 18SS and about 15 Sept. 1 

 succeeded in raising several perfect sawflies. 

 These I was unable to determine or to get 

 determined for me. The past summer I 

 raised one or two more from larvae and cap- 

 tured a number of the sawflies as they were 

 flying about rose bushes. Unable to find any 

 American species to correspond with these, 

 I referred to descriptions of European species 

 and have been able to identify my specimens 

 beyond doubt as Emphytus citictns L. a spe- 



cies common in England and on the Continent- 

 These American specimens also agree in all 

 particidars with European specimens in the 

 Museum of comparative zoology at Cam- 

 bridge. 



7. G. Jack. 



Power of Vision in Vespidae. — • One 

 day in the middle of Juh', while con- 

 fined by illness to my tent on the summit of 

 the Roan Mountains, Col. , I was able to watch 

 at leisure the operations of a couple of wasps 

 which had entered the tent and were search- 

 ing for flies along the tent roof. The tent 

 was an ordinai-y wall tent, 10 ft. X 12 ft., 

 where, Iving upon his back, the observer 

 might readily follow all the movements of 

 these creatures. There were also in the tent 

 perhaps a dozen or twenty flies, mostly col- 

 lected near the ridge pole, especially, when 

 not in flight, alighting upon a rope which 

 stretched from one of the upright poles sup- 

 porting the tent to the other, just below the 

 ridge pole. The wasps were in incessant mo- 

 tion, and in the course of one morning were 

 seen to capture only three or four flies, the flies 

 usually beingable to dodge them whenever an 

 attack upon them was made. I was unable to 

 see that a wasp accelerated its motion in the 

 least when approaching the flies or directed 

 its flight immediately upon them until with- 

 in two or three inches of its intended victim; 

 and as it often passed one by at no greater 

 distance than this without any attempt at 

 capture, the impression was strong that the 

 wasp's distinct vision while in flight did not 

 exceed this distance. But what was most 

 surprising was the great number of mistakes 

 made by the wasps. Every slight stain or 

 defect in the canvas or minute shadow upon 

 it was repeatedly attacked by the wasps as if 

 they supposed it to be a suitable object for 

 food. There seemed to be no power on their 

 part of distinguishing between a spot of color 

 upon the canvas having no elevation what- 

 ever and an object or body resting upon it. 

 Several times the shadow made bv a flv 



