﻿FIELD AND FOREST. 1 69 



tacked by Cecidomyia verbasci, Macq. About fifteen of these galls 

 are known to me. 



Scries II Stems and leaves form the gall. In this series Asparagus 

 is the only monocotyledonous representative. Cecidomyia rosaria on 

 willow aud C. juniperina on 'jPiinipcrus communis are among the 

 twenty examples I have in this series. 



Family II. Closed galls. The larvae bore into the tissues beneath 

 the epidermis, the external wound sometimes remains visible a long 

 time, as in the Cecidomyia galls on Selaginella pentagona {Botanische 

 Ze if ung, 1873, p. IO S-) 



Group I. Mine galls. The larvae live in galleries in the leaves or 

 stems. The parenchyma tissues surrounding the galleries often en- 

 large, especially in compositse, and become hard through the devel- 

 opment of sclerenchyma. They consist of 



I. Leaf miners. (14,) Diptcra, Lepidoptera and some Coleoptera, 

 all in leaves. 



II Enlargements of petioles and stems. 



A. caused by Diptera on dicotyledons. 



Eighteen distortions of various kinds externally visible. Among 

 these Trypela canlui forms curious three to six-chambered galls on 

 Cirsium arvense. 



B-* Distorted receptacles on Composite. 



Sometimes the achenia are modified or the torus is lengthened like 

 a horn or the pappus grows to resemble five green calyx lobes, all o 

 which are secondary appearances, the primary gall is a hard walled 

 larval cavity. (Sixteen species. ) 



(Ik') On Monocotyledons, beside the doubtful stem thickening of 

 lasioptera alisma on Alisma plantago, I am acquainted with eleven 

 of these formations on grasses, some of which are of great interest, as 

 Loncha'a lasiopthalma, Lu., on Cynodon dactylou. These are charac- 

 terized by short opposite leaves, shortened internodes and enlarged 

 nodes. 



B. Caused by Lepidoptera and Coleoptera. Most of these are not 

 galls strictly speaking, but are secondary consequences of wounds re- 

 ceived, as the tumors on trees caused by Carpocapsa, Cossus, Grapho- 

 litha, Tortrix and Incurvaria among butterflies, and Agrilus and Sa- 

 perda among beetles. 



. III. Distortions of flowers and fruit. Caused by eight flies; by an 



