Diastrophus nebulosus

Diastrophus cuscutaeformis

Diastrophus nebulosus n. sp. 

Rubus villosus (?). Blackberry. Elongated, abrupt, pithy swelling on the twigs, from an inch to three inches in length. 

This deformation, chiefly due to a hypertrophy of the pith, in consequence of the sting of the insect, is very common in the environs of Washington. Its color is generally dark red or reddish brown; its shape oblong; its surface generally uneven with irregular tubercles, or with deep longitudinal furrows, dividing the whole gall in four or five parallel ridges. The full-grown specimens are usually 2 or 3 inches long, and from | to an inch in diameter. A transverse section of the gall shows a large number of oblong cells, about 0.13 long, arranged for the most part near the middle of the gall; their intervals are filled with soft pithy matter and harder woody fibres. From galls collected in the fall, the insects usually come out during the winter and in the spring.

Diastrophus cuscutaeformis n. sp. 

Rubus sp. Blackberry. A number of smallround., hollow bodies., forming a cluster round a branch. 

I possess two specimens of this gall, collected near Bladensburgh, Md., and kindly communicated to me by Mr. Hitz. The globular, seedlike bodies, each having about 0.1 in diameter and producing a single insect, are (in one of my galls) from 60 to 70 in number, and occupy a space of about an inch and a half on the branch. They are pressed closely together and offer some resemblance to the seeds of Cuscuta, when found in winter attached to a stem. Many of the round bodies emit more or less strong spines, which impair in a measure the regularity of their form. The consistency of their shell is woody; their color brownish, like that of the branch. I was unable to ascertain on what species of Rubus this gall occurs. Besides the Diastrophus., originating this gall, I have obtained from it an Ormyrus and an Aulax., which, as far as I can judge frum a single specimen, is my A. sylvestris., also reared from the other blackberry- gall.

Contributions to the Natural History of the Cynipidae of the US and of their Galls: article 3