1912] Morphology and Biology of Insect Galls 327 



The unusual type of cell division in the cortex of the hosts infected 

 by certain Lepidopterous forms, e.g. Stagmatophora ceanothiella Cosens 

 and Gnorimo schema gallceasterella Kellicott and described in that group, 

 is also found in the Dipterous gall Neolasioptera perfoliala Felt (Fig. 23). 

 It was not found in any Cynipid form. 



A comparison of a leaf of Abies balsamea (L.) Mill infected by 

 Cecidomyia balsamicola Lintner with one from a witches' broom produced 

 on the same host by Mcidium elatinum (Melampsora Caryophyllacearum) 

 brings out a number of interesting points. These are given in the tabu- 

 lated form following the description of the species C. balsamicola Lintner. 



Order Hymenoptera. 



Following Marlatt's Revision of the Nematinae of North America, 

 U. S. Dept. of Agriculture, Washington (1896), the species considered 

 in this paper are comprised in the Subfamily Nematinae, Family Ten- 

 thredinidae. They are included in two genera, Pontania and Euura. 

 The species referred to are : — 



Euura S. gemma Walsh. 



Euura S. ovum Walsh. 

 *Euura (undescribed). 



Pontania pisum Walsh. 



Pontania pomum Walsh. 



Pontania desmodioides Walsh. 



Pontania hyalina Norton. 

 * Pontania (undescribed). 

 *Gall on Salix lucida (undescribed). 



Gall on Salix humilis (undescribed). 



*Specimens of the first three producers marked (undescribed) were 

 sent to S. A. Rohwer of the Smithsonian Institution. 



I have been successful in rearing the producers of all of the unde- 

 scribed forms except in the case of the one on S. humilis Marsh. This was 

 accomplished in the following manner. The galls were collected at the 

 time of the falling of the leaves of the host plants and were placed on 

 earth in breeding jars which were kept under conditions of heat and 

 moisture approximating as closely as possible to that of the natural 

 habitat. Pupation took place at a distance of about a couple of inches 

 below the surface of the soil and the adults emerged the following spring. 

 The dates of emergence were: — 



Pontania (undescribed), April 14 to April 24. 



Euura (undescribed). May 2 to May 6. 



Gall on 5. lucida (undescribed), April 20 to April 22. 



*While this paper was in press, RohweH* published the description of these producers. 

 Following the order above the names assigned are, — Euura serissima Rohwer, 

 Pontania crassicornis Rohwer, P. lucidm Rohwer. 



