Diastrophus fragariae

Diastrophus fragariae, n. sp.

Gall — On the petiole of Strawberry: Polythalamous, elongate cylindrical swelling tapering at each end. Red and villose like the rest of the petiole. The internal structure is spongy and contains a single row of 5-20 larval chambers. Length from about 25 to 50 mm. Width 3-5 mm. 

Habitat — Toronto, Canada (A. Cosens). 

The gall of this species has long been known. Saunders mentions it in his "Insects Injurious to Fruits," 1887, p. 331, and calls it the Strawberry Leaf-Stem Gall. Prof. S. A. Forbes also mentions the gall in the 22nd Report of the State Entomologist of Illinois, 1883 (1884), p. 97. H. F. Bassett speaks of a Cynipidous gall occasionally seen on the petiole of strawberry leaves (Trans. Am. Ent. Soc, Vol. XXVI, 1900, p. 325). Mr. L. H. Weld found the galls at Ithaca, New York and Evanston, Illinois and I found the same in the vicinity of New York City for some years past. In August, 1913, Mr. A. Cosens collected the gall on wild strawberry in Toronto, Canada. He transplanted some of the infested plants into pots and managed to mature the galls from which he reared five males, being the first one to succeed in obtaining the flies. 

The illustration is from a sketch made by Mr. Weld and re- drawn by Mrs. E. L. Beutenmuller. 

A NEW DIASTROPHUS ON STRAWBERRY