THE SAWFLD2S OF BOULDER COUNTY, COLORADO 95 



(2) X. luteopicta Cockerell. Black; head and thorax much variegated with 

 yellow; legs reddish-yellow; sheath stout, narrowing apically, obtusely pointed; posto- 

 cellar line about half as long as the ocellocular. 



Female; Salina, Boulder County, Colorado, collected April 14, on or about Salix, 

 by T. D. A. Cockerell. 



Two other species of Xyela have been collected in the county. 



Superfamily Siricoidea 



Posterior margin of the pronotum strongly curved; mesonotum extending well 

 beyond the anterior margins of the tegulae; metanotum present; antennae inserted well 

 above the clypeus; anterior wings with more than two cubital cells; propodeum divided 

 by a longitudinal suture; scutellum separated from the mesoscutum by a suture; pro- 

 epimeron wanting; anterior tibiae with one calcaria; cubitus joining the basal vein much 

 below the costa ; ovipositor very long and extending much beyond the tip of the abdomen. 



The insects belonging to this superfamily are commonly called horntails (referring 

 to their long ovipositor and the horn at the apex of the abdomen), or wood- wasps (referring 

 to larval habits). The larvae have only one abdominal foot, are of a pallid color and 

 have many jointed antennae. In all the species known from the county the apex of the 

 abdomen is produced into a triangular shaped plate. They are internal feeders in wood, 

 but their life cycle is but imperfectly known (for American species). It has been stated 

 by some that the larvae take two years to mature, by others it is stated that they mature 

 in one season. 



Family SIRICIDAE 



Notauli wanting; mesoscutum with oblique sutures from the tegulae to the anterior 

 margin of the scutullum; pronotum large, perpendicular anteriorly and angulate laterally ; 

 anterior wings without an intercostal vein; apex of the abdomen with a triangular-shaped 

 plate. 



Subfamily SIRICINAE 



Cerci present; antennae long and slender; transverse median received near the 

 middle of the first discordal cell; second transverse cubitus present. The larvae of this 

 subfamily attack only conifers. 



Tribe Siricini 



Hind tibiae with two calcaria; humerus and transverse median of the hind wings 

 present. 



Genus SIREX Linnaeus 



Apical dorsal plate of the abdomen long, spear-shape in outline; fore wings with one 

 brachial vein, i.e., no vein basad of the transverse median and similar to it; head black, 

 marked with pale; third antennal joint usually a little shorter than the fourth. 



(3) S. flavicornis Fabricius. About 30 mm. (not including the ovipositor) long; 

 black; antennae, posterior orbits, two bands on abdomen, apical appendage, and legs 

 below the femora yellow; wings yellowish hyaline, venation yellowish; pubescence black. 



Recorded from Boulder Canyon, by Cresson, the specimen having been collected 

 by Putnam. 



