596 REPORT OF NEW JERSEY STATE MUSEUM. 



growths as from the insects themselves. The grubs do not feed upon 

 the actual gall tissue, but lie in cells, apparently subsisting upon ma- 

 terial secreted from the inner walls. A gall may have only one larval 

 cell and is then unicellular, or it may have a great many, and is then 

 multicellular. 



The ovipositor in this series is 

 partly coiled within the abdomen, 

 which is usually much dilated and 

 enlarged posteriorly, closely joined 

 to the thorax, but not sessile. The 

 life cycle is often very curious and 

 complicated, and parthenogenesis 

 is of frequent occurrence. In some 

 species there is reason for believ- 

 ing that the males have been com- 

 pletely eliminated, while in others An oak gall-fly. 

 there is an alternation of genera- Fig - 241 - 

 tions, one having both sexes nor- 

 mally present, while in the other the females only occur. None of the 

 species are really harmful, nor, in this country, are any. of them useful, 

 though in some European countries galls are commercially important. 



The completeness of the records in this family is due to the pains- 

 taking work of Mr. William Beutenmuller, whose collections in the 

 vicinity of New York City are models of thoroughness. Only those species 

 are included that have been actually found in New Jersey, or whose dis- 

 tribution in connection with the food plant makes it almost certain that 

 careful collection will demonstrate its presence. 



Family 



Contains those species that are parasitic in most instances. 



^ 



EUCCELIDIA Ashm. 



E. canadensis Ashm. (Figites) Long Island, and almost surely New Jer- 

 sey. 



SOLENASPIS Ashm. 

 S. armatus Say. New Jersey (Ashm). 



EUCCELA Westw. 



E. pedata Say. New Jersey district. 



E. stigmata Say. Jamesburg VII, 15 (Sm). 



E. impatiens Say. (Psilodera) Jamesburg VII, 15 (Sm). 



