Eurytoma hyalipennis. 



The galls caused by this species on the marum grass are 

 very interesting. The larva lives within the upper part of the 

 haulm, and by its ravages prevents the further extension of that 

 portion of the plant. The leaves, however, continue their 

 growth, but not in the usual manner. The basal portion of one 

 leaf spreads itself around another from the opposite side of the 

 stem ; that leaf in turn is enveloped within another. This 

 arrangement is multiplied until fifteen or twenty will thus 

 embrace each other, forming a spindle-shaped bundle of stunted 

 leaves. The leaves, converging just above the gall, continue to 

 grow for a few inches, and assume their ordinary needle-like 

 appearance. If the leaves be carefully removed, the gall proper 

 will be readily found. It consists of a cylindrical-shaped 

 swelling of the haulm, and shows on its surface where the leaves 

 are attached to it. When cut open in the plane of its growth, 

 the larval chamber will be seen. This cavity in some specimens 

 is 40 mm. long and 2 mm. in diameter. The imagines emerge 

 during June from the galls of the pre\ious year and immediately 

 attack the tops of the young and tender haulms. By the end of 

 July the galling agency is plainly visible, and at the end of 

 September the larva is fully grown. It remains in an inactive 

 condition through the winter, pupates within the gall during 

 the spring, and emerges in June. The galls are seldom more 

 than 12 in. above the level of the sand. Among several 

 hundreds the author has collected and examined, none have been 

 seen with two on one haulm. 



The illustration is of specimens gathered at Camber, near 

 Rye, by the author. 



