THE ENTOMOLOGIST. 451 



of Matricaria; feeds in the receptacle, and forms a cocoon 

 in it." 



Mecinus collaris, Germ. ''From galls on Planta^o mari- 

 tima; the Hymenoptera (Pteromalus imbutus, Wlk.) are 

 parasitic on that beetle, and are found in its galls, and form 



a close-fitting case. The small gnats (Cecidomyia sp ?) 



were also reared out of that plant." 



One specimen of Tetrastichus Diaphantus, JVlk., accom- 

 panied the three preceding species : it is, probably, parasitic 

 on the Cecidomyia. 



Three species were reared by Mr. MoncreafF from the stem 

 of the dock. 1. A little Dipterous fly (Muscidae) unknown 

 to me. 2. A species of Cynipidas. 3. Syntomopus incurvus, 

 TVlk., probably parasitic on the Dipterous insect. 



"From the willow herb." The fly much resembles Tetras- 

 tichus Adalia, Wlk., but the antennae seem to be darker and 

 stouter. 



Bracon tenuicornis, Wesm., and Isosoma hyalipennis, IVlk., 

 from Triticum repens.- 



" The galls in the stems of Festuca ovina are of two sorts : 

 one single-celled, and containing only one larva ; the other 

 many-celled, and each cell containing one larva. 



" Last autumn I separated these as closely as I could, and 

 placed each description of galls in close-corked bottles, and 

 I felt somewhat confident that by this means I should 

 discover the true gall-maker, which 1 fully expected to 

 emerge from the single-celled gall. I now send you the flies 

 that emerged in May and June." The flies from the single- 

 celled galls are Eurytoma collaris, Wlk. The flies from the 

 many-celled galls are Eurytoma collaris, Isosoma depressa, 

 Wlk., Decatoma mellea, Wlk., Pteromalus fulviventris, Wlk,, 

 and Trigonoderus hirticornis, Wlk. f The Isosoma was the 

 most numerous, and next to it the Pteromalus and the 

 Decatoma; the Eurytoma was few in number; and of the 

 Trigonoderus there were only two specimens. The Ptero- 

 malus and the Trigonoderus may be considered to be parasitic 

 on the three genera of Eurytomidae, and this family, of which, 

 among all the Chalcidites, the abdominal structure most 

 resembles that of the Cynipidae, appear to be occasionally 

 gall-makers, and occasionally dwellers in galls made by 

 other insects. — Francis Walker. 



