Mar., 1909.1 ROHWER : CrYTOCAMPUS IN BOREAL NORTH AMERICA. 19 



long or slightly longer than the sheath above. Black : face below the antennoe, 

 clypeus, labrum, mandibles (apex black), narrow inner orbits, posterior and superior 

 orbits broadly (the lower posterior orbit is sometimes black), posterior angles of pro- 

 notum, teguliie, legs (posterior tarsi dusky), abdomen except a broad dorsal band and 

 apex of the sheath, /ez-rusfinous. Palpi brownish. Apical joints of antennas beneath 

 sometimes slightly yellowish. Wings slightly dusky hyaline, iridescent ; venation 

 brown, costa and base of stigma subpallid. 



AfaU. -Length 5 mm.; length of anterior wing 5.25 mm. Structurally the 

 male is much like the female. The clypeus is sometimes more shallowly emargi- 

 nate. The frontal crest is hardly broken. The middle fovea is rather shallow and 

 elongate. The furrows and ocellar basin are usually more sharply defined. The 

 orbits are usually black, but sometimes iheyare ferruginous. The antennal joints are 

 longer ; the apical joint is distinctly longer than the preceding one. The apex of 

 the posterior tibte and their tarsi are black. The abdomen is either entirely black, or 

 only the apical part of the venter is ferruginous. The antennae are ferruginous 

 beneath. Procidentia broad, rather short, truncate. Hypopygium slightly exceed- 

 ing the abdomen, rounded at apex. Stigma and costa black. 



Habitat. — Boulder, Colorado (S. A. Rohwer). Many males and 

 females bred from galls made on Salix bebbiana (.?). Hatching April 

 8-18, 1907. 



Gall zn abrupt elongate swelling on the twigs of Salix bebbiance ? 

 Color that of the twig ; when green usually smooth, but in drying 

 thrown into shallow, broad wrinkles. It is always monothalamous. 

 Sometimes galls are made on each side of a twig directly opposite, 

 but usually they are made at intervals of two to three centimeters 

 on opposite sides of the twig. In one case a gall on one side of 

 the twig, directly opposite another gall which was matured, was 

 stunted, giving the mature gall the appearance of an abrupt enlarge- 

 ment of the twig at the base, gradually tapering at the apex. When 

 the egg is laid on a very small twig, as it was in one case noticed, 

 the gall is higher, shorter, broader and subovate. The measurements 

 of this gall are as follows ; length ii mm. ; breadth 9 mm. ; height 

 8.5 mm. Disregarding the gall just measured, the length varies from 

 18 to 35 mm., the height at base from 8 to 1 1 mm., the height at 

 apex from 4 to 6 ram., the width at base from 7 to 1 2 mm., the 

 width at apex from 3 to 7 mm. The larva works downward, the base 

 of the gall being the largest. In the largest part of the gall where the 

 pupal stage is passed, the chamber is larger. 



The larva is about 5 mm. long, creamy-white, with a dark brown 

 head. I am not sure that the larva makes the hole through which the 

 adult emerges in this species as it does in macgillivrayi, but think that it 

 does not. The hole is on the side of the gall a little way above the base. 



