Colocistis Krombein 1942

Male Body length 5–16 mm. Head. Compound eyes and ocelli enlarged (except quite small in Colocistis chemsaki and Colocistis pilosa); gular carina either not elevated or elevated gradually at level of posterior mandibular condyle, not suddenly produced apically, clypeal length versus width ratio not exceeding 0.35; maxillary and labial palpi not reduced, maxillary palpi six-segmented, exceeding posterior border of gular orifice by half length of palpus; labial palpi four-segmented. Mesosoma. Fore wing with costa extending beyond stigma for a distance not over half length of stigma; forewing with two discoidal cells and two or three submarginal cells, second submarginal cell completely or almost completely underlying first submarginal cell, first transverse cubital vein arising at or before basal third of second submarginal cell (Fig. 14); hind wing with cubitus arcuately curved, longer that first transverse cubital vein and meeting it at an angle of less than 135 degrees; hind wing with jugal lobe shorter than submedial cell; forecoxa with admesal stridulatory area; hindcoxa with longitudinal carina on inner margin. Metasoma. Sternum II without basal longitudinal carina (one species with transverse carina); digitus of genitalia without process extending distad of articulum; volsellar plate without spines or teeth, but with flexible hairs on mesal surface.

Colocistis species are found in southeastern California, southern Nevada, southern Arizona, southern Colorado, western Texas and as far south as Oaxaca, Mexico. Key to species of Colocistis 1 Wingless, metasoma 6-segmented; females 2 – Winged, metasoma 7-segmented; males 5 2 Gular carina strongly elevated or angulate on either side of midline, meeting occipital carina (as in Fig. 11); meso-metapleural suture obsolescent; metasomal sternum I with medial, longitudinal sulcus present on basal third 3 – Gular carina linear or crenulate, not elevated or angulate on either side of midline, interrupted medially occipital carina incomplete laterally, not meeting gular carina (as in Fig. 12); meso-metapleural suture present, distinct; metasomal sternum I with medial, longitudinal sulcus present on more than half of length 4 3 Gular carina interrupted medially, with strongly developed submedial tooth or angle, meeting occipital carina at distinct angle (Fig. 11); transverse carina posterior to gular carina medially interrupted, without curved angles or lobes; meso-metapleural suture absent or only faintly visible in certain views Colocistis segredentata Mickel & Krombein – Gular carina not interrupted medially, strongly developed submedial rounded lobe (Fig. 10); gular carina meeting occipital carina in even curve; transverse carina posterior to gular carina with two low, rounded prominences behind lobes of gular carina; meso-metapleural suture faint but distinct Colocistis eureka (Banks) 4 Gular carina extending laterally considerably beyond where occipital carina would terminate if present (Fig. 12); vertex foveae linear, consisting of row of contiguous pits; metasomal sternum I medial, longitudinal sulcus extending complete length of sternum, sulcus narrow and deep anteriorly, broad and shallow posteriorly Colocistis sulcata Mickel & Krombein – Gular carina not extending laterally beyond where occipital carina would terminate if present; vertex foveae short, elliptical; metasomal sternum I medial, longitudinal sulcus same width throughout, deeper anteriorly than posteriorly Colocistis paxillata Mickel & Krombein 5 Forewing with two submarginal cells (as in Fig. 13); hindcoxal carina low and indistinct 6 – Forewing with three submarginal cells (as in Fig. 14); hindcoxal carina prominent 8 6 Gular carina elevated anteriorly (as in Fig. 9) Colocistis eremi (Bradley) – Gular carina not elevated anteriorly, nearly linear 7 7 OOL 1 ocellar diameter or less; vertex not visible behind ocelli in full frontal view (Fig. 1); gonostylar apical margin evenly curved to acute apex (Fig. 49) Colocistis brevis (Cresson) – OOL 2 ocellar diameters or more; vertex clearly visible behind ocelli in front view (Fig. 3); gonostylar apical margin truncate or slightly emarginate (Fig. 51) Colocistis chemsaki sp. n. 8 Metasomal sternum II basally slightly raised and separated from posterior part by transverse declivity (as in Figs 19, 22) 9 – Metasomal sternum II without raised area basally (as in Fig. 20) 10 9 Head and body black; ocelli small, diameter of lateral ocellus 0.5× OOL (Fig. 7); clypeus with median tubercle (Fig. 7); aedeagus in lateral view evenly curved, simple at apex (Fig. 55) Colocistis pilosa Krombein – Head and body castaneus; ocelli enlarged, diameter of lateral ocellus at least 0.7× OOL (Fig. 4); clypeus without median tubercle (Fig. 4); aedeagus in lateral view suddenly decurved, apex with a dorsally projecting process Fig. 52) Colocistis crassa (Bradley) 10 Clypeus with a projecting tubercle, plainly visible above mandibles in full lateral view, area between tubercle and apex appearing beveled (Fig. 8); genitalia in lateral view with gonostyli straight or slightly concave at apex; aedeagus decurved before apex (Fig. 56) Colocistis thermarum (Bradley) – Clypeus somewhat flattened and depressed, not visible above mandibles in full lateral view, apex not beveled; genitalia in lateral view with gonostylus strongly excavate at apex; aedeagus not decurved before apex (as in Figs 50, 54) 11 11 Integument of head, mesosoma and first metasomal segment lighter in color than remainder of metasoma; head in full frontal view (Fig. 6) with vertex arched far above ocelli; genitalia in lateral view (Fig. 54) with apex of gonostylus nearly straight Colocistis oaxacana sp. n. – Integument of entire body concolorous; head in full frontal view with vertex arched only slightly, if at all, above ocelli (Fig. 2); genitalia in lateral view (Fig. 50) with apex of gonostylus strongly excavate Colocistis castanea (Cresson)

Male Body length 5–16 mm. Head. Compound eyes and ocelli enlarged (except quite small in Colocistis chemsaki and Colocistis pilosa); gular carina either not elevated or elevated gradually at level of posterior mandibular condyle, not suddenly produced apically, clypeal length versus width ratio not exceeding 0.35; maxillary and labial palpi not reduced, maxillary palpi six-segmented, exceeding posterior border of gular orifice by half length of palpus; labial palpi four-segmented. Mesosoma. Fore wing with costa extending beyond stigma for a distance not over half length of stigma; forewing with two discoidal cells and two or three submarginal cells, second submarginal cell completely or almost completely underlying first submarginal cell, first transverse cubital vein arising at or before basal third of second submarginal cell (Fig. 14); hind wing with cubitus arcuately curved, longer that first transverse cubital vein and meeting it at an angle of less than 135 degrees; hind wing with jugal lobe shorter than submedial cell; forecoxa with admesal stridulatory area; hindcoxa with longitudinal carina on inner margin. Metasoma. Sternum II without basal longitudinal carina (one species with transverse carina); digitus of genitalia without process extending distad of articulum; volsellar plate without spines or teeth, but with flexible hairs on mesal surface.

Colocistis species are found in southeastern California, southern Nevada, southern Arizona, southern Colorado, western Texas and as far south as Oaxaca, Mexico. Key to species of Colocistis 1 Wingless, metasoma 6-segmented; females 2 – Winged, metasoma 7-segmented; males 5 2 Gular carina strongly elevated or angulate on either side of midline, meeting occipital carina (as in Fig. 11); meso-metapleural suture obsolescent; metasomal sternum I with medial, longitudinal sulcus present on basal third 3 – Gular carina linear or crenulate, not elevated or angulate on either side of midline, interrupted medially occipital carina incomplete laterally, not meeting gular carina (as in Fig. 12); meso-metapleural suture present, distinct; metasomal sternum I with medial, longitudinal sulcus present on more than half of length 4 3 Gular carina interrupted medially, with strongly developed submedial tooth or angle, meeting occipital carina at distinct angle (Fig. 11); transverse carina posterior to gular carina medially interrupted, without curved angles or lobes; meso-metapleural suture absent or only faintly visible in certain views Colocistis segredentata Mickel & Krombein – Gular carina not interrupted medially, strongly developed submedial rounded lobe (Fig. 10); gular carina meeting occipital carina in even curve; transverse carina posterior to gular carina with two low, rounded prominences behind lobes of gular carina; meso-metapleural suture faint but distinct Colocistis eureka (Banks) 4 Gular carina extending laterally considerably beyond where occipital carina would terminate if present (Fig. 12); vertex foveae linear, consisting of row of contiguous pits; metasomal sternum I medial, longitudinal sulcus extending complete length of sternum, sulcus narrow and deep anteriorly, broad and shallow posteriorly Colocistis sulcata Mickel & Krombein – Gular carina not extending laterally beyond where occipital carina would terminate if present; vertex foveae short, elliptical; metasomal sternum I medial, longitudinal sulcus same width throughout, deeper anteriorly than posteriorly Colocistis paxillata Mickel & Krombein 5 Forewing with two submarginal cells (as in Fig. 13); hindcoxal carina low and indistinct 6 – Forewing with three submarginal cells (as in Fig. 14); hindcoxal carina prominent 8 6 Gular carina elevated anteriorly (as in Fig. 9) Colocistis eremi (Bradley) – Gular carina not elevated anteriorly, nearly linear 7 7 OOL 1 ocellar diameter or less; vertex not visible behind ocelli in full frontal view (Fig. 1); gonostylar apical margin evenly curved to acute apex (Fig. 49) Colocistis brevis (Cresson) – OOL 2 ocellar diameters or more; vertex clearly visible behind ocelli in front view (Fig. 3); gonostylar apical margin truncate or slightly emarginate (Fig. 51) Colocistis chemsaki sp. n. 8 Metasomal sternum II basally slightly raised and separated from posterior part by transverse declivity (as in Figs 19, 22) 9 – Metasomal sternum II without raised area basally (as in Fig. 20) 10 9 Head and body black; ocelli small, diameter of lateral ocellus 0.5× OOL (Fig. 7); clypeus with median tubercle (Fig. 7); aedeagus in lateral view evenly curved, simple at apex (Fig. 55) Colocistis pilosa Krombein – Head and body castaneus; ocelli enlarged, diameter of lateral ocellus at least 0.7× OOL (Fig. 4); clypeus without median tubercle (Fig. 4); aedeagus in lateral view suddenly decurved, apex with a dorsally projecting process Fig. 52) Colocistis crassa (Bradley) 10 Clypeus with a projecting tubercle, plainly visible above mandibles in full lateral view, area between tubercle and apex appearing beveled (Fig. 8); genitalia in lateral view with gonostyli straight or slightly concave at apex; aedeagus decurved before apex (Fig. 56) Colocistis thermarum (Bradley) – Clypeus somewhat flattened and depressed, not visible above mandibles in full lateral view, apex not beveled; genitalia in lateral view with gonostylus strongly excavate at apex; aedeagus not decurved before apex (as in Figs 50, 54) 11 11 Integument of head, mesosoma and first metasomal segment lighter in color than remainder of metasoma; head in full frontal view (Fig. 6) with vertex arched far above ocelli; genitalia in lateral view (Fig. 54) with apex of gonostylus nearly straight Colocistis oaxacana sp. n. – Integument of entire body concolorous; head in full frontal view with vertex arched only slightly, if at all, above ocelli (Fig. 2); genitalia in lateral view (Fig. 50) with apex of gonostylus strongly excavate Colocistis castanea (Cresson)