Callirhytis seminator (sexgen)

On Callirhytis seminator. (Cynipoidea, Hym,). 

This beautiful gall is common in the vicinity of Blacksburg, Virginia, on white oak. A number of them were collected on June 24, 1903: at that date their age varied, but adults were emerging from the mature galls. The young galls consist of a radiating mass of larval cases on a common receptacle at the end of a twig at the base of a leaf petiole. Each larval case is surmounted by a glossy white substance resembling glass wool, and which by combination with that of adjoining cases forms a complete, globular and more or less compact woolly ball. As the galls increase in size and approach maturity, the larval cases lengthen from their distal end and push the woolly substance out into point-like protuberances. The galls turn brown when maturing. They may also be found along the side of a twig, in one case the receptacle being formed on a developing bud. The eggs of this cynipid are probably deposited within a bud. The galls are large and conspicuous, flower-like at times and bitter to the taste. There are commonly two receptacles, side by side, in the place of the two apical buds of the twig. 

The young larval cases are seedlike and measure about three millimetres; they taper at the distal end and each bears a tuft of woolly substance. In the mature galls each case has become elongated into fleshy spokes, green and herbaceous, which measure about thirteen mm. in length, about half of which is the elongated distal end. 

The adults issue through large holes at one side of the distal extremity of the larval case (the basal, swollen, seed- like portion of it) and tunnel their way through the surrounding substance to the open air, leaving for the time being a small shotlike hole; these soon close up owing to the nature of the gall substance. The adults emerge for a period of at least two weeks. The gall also occurs at Cumberland, Maryland. 

Parasites are numerous; a golden-haired Eurytomid was reared from the Virginia specimens. 

Fragments on North American insects II