68 H. F. BA8SETT. 



a very deep line over the base of each wing and a short niedian line from the 

 scutellum, wliich does not reach forward to the parallel lines just mentioned ; 

 foveje wanting. Abdomen black, the second segment with hairs on the sides. 

 Legs dark reddish brown, the tarsi darkerand rather dusky, ungues two tootlied. 

 Wings large, hyaline ; veins slender, dark; areolet small, cubitus only reaching 

 two-thirds the way to the first transverse, radial area open and of usual size. 



I do not give measurements of this species as the flies were not 

 naturally developed, but they are probably about the same size as 

 H. eoraUhms and H. canescens. The naturally hatched insects may 

 vary somewhat from this description, but the galls are sufficiently 

 distinct to establish this as a new species. I give it the name of the 

 discoverer, A. H. Siler, 

 5. H. periiiciosiis n. sp. 



Monothalamous, roundish galls, sessile by a broad base on the 

 twigs of a dwarf oak growing in southern Utah. Apex in some 

 specimens slightly elongated and compressed laterally, but usually 

 blunt cone shaped. The twig itself is enlarged into a shallow cup-like 

 receptacle at the base of the gall. In all my specimens ( dry ones from 

 which the insects have escaped) the galls are smooth, or only slightly 

 rough, and with deep, irregular cracks and a dark reddish brown color. 

 The large larval cell is firmly imbedded in the rather hard cellular 

 tissue. The insects escape through a large opening which they make 

 near the base of the gall. These galls bear a pretty close resem- 

 blance to the parasitized galls of H. duricoria Bass. Judging from 

 their abundance on the twigs sent me they must be quite injurious 

 to the trees infested. Cutting open several of the un perforated galls, 

 I was so fortunate as to find several dead, but perfectly developed 

 gall-flies, all females. 



Gall-flies. — Head deep dusky red, face dark, almost black in the centre; ver- 

 tex with a broad dark band in the middle enclosing the ocelli and extending to 

 the base of the anteunpe. Antennse brownish black, shining; first joint large, 

 second ovate, third slender and a little longer than the first two taken together, 

 fourth, fifth, sixth and seventh gradually shorter, remaining joints of uniform 

 length. Thorax dark reddish brown ; in a strong light appearing black and cov- 

 ered with white hairs: surface punctulate, parallel lines broad, reaching half 

 way to the scutellum; median line very fine and indistinct, parapsidal grooves 

 distinct on the scutellum, but disappearing half way to the collare. Lines over 

 the base of the wings distinct, close to and parallel with the parapsidal grooves ; 

 scutellum light red, hairy, regularly rounded posterorly, fovefe vvanting. Ab- 

 domen black and shining, first segment large, the sides sparsely covered with 

 rather long, white hairs; sheath of the ovipositor with fine short hairs. Legs 

 dark reddish brown, paler at the joints, the ungues black, simple. Wings hya- 

 line, veins dark reddish brown, shining ; areolet rather large, distinct ; cubitus 

 slender, and disappearing half way to the first transverse, radial area open. 

 Length: body, .14 inch.; wings and antennse medium length, not measured. 



