184 



PSYCHE. 



[April 1S89. 



galls of A. spongijica., for which they 

 are often mistaken, by occurring on ^, 

 coccittea and ^. nigrum ( ?) instead of 

 ^. r7ibra., by having a thinner outer 

 shell, by having the surface more glossy 

 and covered with small pimples, and by 

 having the inner radiating substance 

 matted about the central cell, from which 

 it can easily be removed with the fingers, 

 instead of having these fibers grown into 

 a hard w^oody center surrounding the 

 larval cell. The fly leaves the gall 

 about the middle of June and its gen- 

 eral color is a reddish brown. A. 

 spougijica has two dates for appearing, 

 a portion of the flies emerging in June 

 and the remainder in October, and the 

 general color of this species is black. 



My specimens of ^4. coccinea began 

 appearing June i6th. Neither guest 

 nor parasites were reared. 



A7nphibolips spongifica O. S. ( Cy- 

 nips conjluens Harris, and C. acicitlata 

 O. S.) Walsh speaks of this species 

 in the Ainerican e7itoniologi st as oc- 

 curring plentifully on the black oak, J^. 

 nigrum^ but, although I have seen 

 great numbers of these galls in both 

 Michigan and Iowa on the leaves of J^. 

 rubra., I have yet to find one on the 

 leaves of J^. tiigrum. The only flies 

 that I have reared from these galls are 

 those of the late part of the brood which 

 began to appear October 3. On the 

 13th of October forty- seven galls were 

 opened which gave seven true gall-flies, 

 twenty-seven parasitised galls and the 

 remainder blanks. 



Amphibolips sculpta Bass. The 

 beautiful translucent galls produced by 



this species I have taken on the leaves 

 of ^. rubra and ^. coccinea. They 

 ai"e attached to the under side of the 

 leaves and may well be likened to large 

 Deknvare grapes in appearance. Galls 

 taken in Michigan began giving flies 

 June 21. Eight of these galls taken 

 July 5 in the vicinity of Ames, Iowa, 

 gave only parasites, two beautiful species 

 of Torynius. No guests were reared. 

 Amphibolips inanis O. S. The gall 

 of this fly is very common on the leaves 

 of ^uercus rubra. Large specimens 

 are an inch in diameter. The galls are 

 composed of a thin outer shell connected 

 with the central larval cell by many 

 thread-like radiating fibers. The flies 

 begin to appear about the 20th of June. 

 Over 90 per cent of the galls that I have 

 collected have contained parasites. In 

 the majority of cases, the central cell 

 has been found to be crowded full of the 

 parasitic larvae of what I take to be a 

 species of Tetrastichus. There is also 

 a large species of Torymus that I have 

 found common in these galls. 



AuipJiibolips pr7t7i?is Walsh. A sin- 

 gle specimen of what seems to be the gall 

 of this species was taken from the cup of 

 a black oak (J^. nigrum) about the mid- 

 dle of August. The gall was immature 

 and no insect was reared from it. 



Andricus clavula Bass, The red 

 swollen tips of the twigs of ^uercus 

 alba., which are the galls of the above 

 named gall-fly, are very common in 

 Michigan and Iowa. From these galls 

 I have reared several specimens of the 

 guest, Ceroptres petiolicola., but no true 

 "rail-flies. 



