1912] Morphology and Biology of Insect Galls 339 



August nth. — Galls were found in which the ovipositing could have 

 taken place only a few hours before. The ovipositing in this species must 

 continue over a period of at least two months. 



Pontania pomum Walsh. 

 Pontania desmodioides Walsh, 



These producers begin to oviposit at about the same date as the 

 above species. The period of ovipositing must comprise a comparatively 

 short space of time as the galls of these species are all at about the same 

 stage of development on the same date. 



The galls produced respectively on Salix cordata Muhl. and Salix 

 humilis Marsh, by these producers are not found near the tips of the 

 young stems, but the galls on Salix alba L. produced by Pontania hyalina 

 Norton are found on leaves along the whole length of the young stems. 

 This difference in the location of the galls is caused by the period of ovi- 

 positing being much longer in Pontania hyalina Norton than in the other 

 two species. 



The first effect of ovipositing by Pontania pomum Walsh, visible to 

 the unaided eye, is a dark red colour produced in the leaf blade surround- 

 ing the spot where the ovipositor has entered. This colour is also visible 

 for a short distance along the midrib of the leaf. When the gall is opened 

 at this stage the egg of the producer can be found with the aid of a lens. 

 It is elliptical in outline and of pearly lustre. The membrane is trans- 

 lucent and the egg contents can be distinguished through it. 



Order Hymenoptera. 



Whenever possible the specific names have been selected from the 

 monographs by Wm. Beutenmuller,^-''' that are now being issued from 

 the American Museum of Natural History, New York. These publica- 

 tions give full synonymy and bibliography of the different species. 



The following species are here described : — 

 Fam. Cynipidae. 



Holcaspis globulus Fitch. 



Holcaspis bassetti Gillette. 



Philonix erinacei Beut. 



Philonix hirta Bassett. 



Philonix nigra Gillette. 



Amphibolips confluens Harris. 



Amphibolips inanis O.S. 



Dryophanta palustris O.S. 



Andricus imbricaricB Ashmead. 



Andricus singularis Bassett. 



