Reprinted with permission from: Daly, H. V. 1973. Bees of the genus Ceratina in America North of Mexico (Hymenoptera: Apoidea). University of California Publications in Entomology 74: 1-114. The Regents of the University of California. Published by the University of California Press.
Ceratina sequoiae Michener, 1936
Female.—Measurements and ratios: Wing, 4.4 mm; hamuli, 5; eye, 100:110:115:115; clypeus, 50 × 105:30:80; interocellar, 20:40:35:60, Ø 15.0; frontal carina, 55; malar area, 0 × 40; interalveolar, 27:25:40:47, Ø 18; antennae, 50:15:15:10:8:10, Ø 12; subpleural signum, 17 x 2.5 (paratype from type locality).
Structure: Read quadrate in cephalic view; eyes slightly divergent below, narrowly rounded above, subtruncate at malar area; frontal carina simple, sulciform between alveolocellar areas and vanishing beneath median ocellus; supraclypeal, interalveolar, and alveolocellar areas gently convex; vertex and supraorbital areas limited posteriorly by preoccipital carina; median portion of hypostomal caring when viewed laterally moderately elevated, highest anteriorly where it terminates in right-angled tooth, when viewed ventrally the angle between the median and lateral portions is about 130. Pronotum with transverse carina basal in position and sharp medially, becoming blunt laterally; anterolateral surface of mesopleuron flattened and, beneath pronotal lobe, surface strongly angled to create distinct impunctate anterior face; basitibial plate acute, its elevated apex at basal 0.23 of tibial length. Metasoma widest at segment 4; gradulus of tergum 4 terminating laterally beyond and below spiracle at a distance of 2.0 spiracle lengths; tergum 6 with slight central concavity; graduli of sterna 2-a transverse and nearly straight.
Sculpture and vestiture: Head shiny between punctures, largely impunctate on mandible base, clypeal disc, lowest portions of supraclypeal and paraocular areas, upper subantennal area, alveolocellar area and laterally in narrow band which extends posteriorly around eye; elsewhere with fine punctures often as close as a puncture width apart, and with largely simple setae; punctures closer in interalveolar area and in single row in alveolorbital area; punctures widely spaced on lateral part of gena, setae longer in interalveolar area, vertex, postgena, labral disc, and mandible. Sides of pronotum moderately and contiguously punctured, impunctate area before pronotal pit; scutal disc shiny, fine punctures sparsely along lines, denser to less than a puncture width apart around margin and on axilla; scutellar disc impunctate, fine punctures marginally becoming closer and less than a puncture width apart laterally and posteriorly; metanotum with fine punctures about a puncture width apart; mesopleuron with coarse punctures which are contiguous anterolaterally and often coalescent to produce irregular foveolae, punctures becoming round and more than a puncture width apart posteriorly; hypoepimeral area punctured throughout; metapleuron with fine punctures about a puncture width apart, impunctate before metapleural pit; propodeal triangle of reticulate carinulae of which few are clearly longitudinal; angle of propodeum rounded, impunctate, minutely coriaceous; sides finely punctured, becoming contiguous and smaller laterad, with erect, long plumose setae. Metasomal tergum 1 finely punctured on dorsal surface, several puncture widths apart, impunctate on anterior surface; terga 2-5 with scattered fine punctures on pregradular area near gradulus; postgradular punctures of two types, fine and extremely minute (visible at 50 x), both types several puncture widths apart, more widely spaced on discs of more anterior terga, each type of puncture with a short, appressed, simple seta, ground shiny but subapically papillate on terga 2-4; tergum 5 papillate throughout; tergum 6 finely punctured about a puncture width apart, ground papillate basally, becoming rugulose apically, central area punctate but not papillate; setae on terga short, simple, except longer laterally on tergum 6. Sterna finely punctured, about a puncture width apart; setae simple, coarse, suberect, dense at abdominal apex; setae of wax glands appressed.
Color: Body metallic dark olive green (ISCC.NBS 126), metallic colors lacking on labrum, mandibles, mesoscutal disc, and wax glands. Ivory marks: amygdaliform on clypeus, extending almost the full length of clypeus; spots of subequal size at bases of all tibiae; pronotal lobes. Antennae fuscous, lighter beneath; legs proximally fuscous, femora and tibiae faintly metallic, tarsi apically testaceous; tegula testaceous; wing membrane hyaline, venation dark testaceous. Body setae pale flavescent to white.
Male.—Measurements and ratios: wing, 4.0 nun; hamuli, 6; eye, 100:105:90:80; clypeus, 50 × 75:25:80; interocellar, 18:35:25:45, Ø 15.0; frontal carina, 55; malar area, 0 × 40; interalveolar, 20:20:40:45, Ø 20; antenna, 35:10:11:10:10:16, Ø 15; subpleural signum, 17.5 × 3. (Oakhurst, Madera County, California; California Insect Survey)
Structure: Head rounded in cephalic view; eyes convergent below, narrowly rounded above, broadly rounded at malar area; frontal carina simple, distinct between alveolae, sulciform beneath median ocellus; vertex and supraorbital area limited posteriorly by preoccipital ridge with a low carina; median portion of hypostomal carina when viewed laterally of low uniform height, terminating anteriorly without a tooth, when viewed ventrally lateral portion arcuate. Ventral profile of metatrochanter rounded, apical anteroventral facet obscure, polished; width of metafemur at tooth slightly less than 0.5 length, tooth rounded, obtusely 130’ angled, basal anteroventral facet, distinct, polished concave surface, ventral edge with sparse, very long, narrowly plumose setae (resembles fig. l0g, ventral hair longer). Metasoma widest at segment 3; gradulus of tergum 4 terminating laterally beyond and below spiracle at a distance of 3.0 spiracle lengths;
tergum 6 without median subapical protuberance (resembles ilk); dorsal view of apical plate width 2.0 times length broadly rounded; sternum 6 with one median tooth divided at apex (resembles fig. 12c). Genitalia presumed to be similar to fig. 29a.
Sculpture and vestiture: Head shiny between punctures, largely impunctate on clypeal disc, subantennal area, most of convex portion of alveolocellar area and in narrow band behind eye; sparse, fine punctures on mandible base; gena with fine punctures irregularly about a puncture width apart; elsewhere with fine to medium punctures about a puncture width apart and with largely simple setae; punctures closer in interalveolar area, sparser in ocellorbital area; sparse setae longer in interalveolar and postgenal areas, vertex, labral disc and posteriorly on mandible. Sides of pronotum finely and punctured less than a puncture width apart, impunctate area above pronotal pit extending to beneath dorsolateral angle; scutal disc shiny, virtually impunctate except moderately along lines, fine punctures marginally and less than a puncture width apart laterally and on axilla; scutellar disc moderately punctate, fine punctures becoming less than a puncture width apart laterally and posteriorly; metanotum finely and almost contiguously punctured throughout; mesopleuron with medium punctures about a puncture width apart or less
laterally, becoming more widely spaced posteroventrally, long plumose setae; hypoepimeral area punctured throughout; metapleuron finely punctured, usually less than a puncture width apart; small impunctate area before metapleural pit; propodeal triangle minutely rugulose; angle of propodeum impunctate, minutely coriaceous; sides finely punctured, becoming contiguous and smaller laterad, with erect, plumose setae. Metasomal tergum I finely punctured on dorsal surface about a puncture width apart, virtually impunctate on anterior surface; terga 2-6 with scattered fine punctures on pregradular area near gradulus, postgradular punctures fine and uniformly about 1—2 puncture widths apart, each with a short appressed simple seta; ground shiny, but
minutely roughened on terga 5-6; tergum 7 finely punctured two or more puncture widths apart with shiny ground, apical plate above with long, spreading plumose hairs extending beyond plate. Sterna 1-5 finely punctured, two to three puncture widths apart; setae fine, suberect, narrowly plumose, longer subapically on each sternum.
Color: Head and thorax metallic very dark greenish-blue (ISCO-NES 175) with minor yellowish reflections; abdomen more olive green with cuticle beneath metallic reflections dark fusco-rufous; metallic colors lacking on mandibles which are black basally. Ivory marks: broad hat-shaped on clypeus, extending full length and width; irregular triangular spot on labral disc; spots at bases of all tibiae, being largest on metatibia; pronotal lobes. Antennae blackish, lighter beneath; legs proximally dark fuscous, femora and tibiae faintly metallic, tarsi apically testaceous; wing membrane hyaline, venation and tegula dark testaceous. Body setae pale flavescent.
Male compared with illustrations of other specimens: metafemur and metatrochanter (fig. l0g), sternum 6 and apical plate (fig. 12c); genitalia not dissected, but illustrated from another specimen (fig. 29a).
The females of Ceratina sequoiae are distinguished among California Ceratina by the coarse, irregular mesopleural punctation with the punctures distorted and confluent beneath and in front of the hypoepimeral area. The region is also flattened and its surface forms a right angle with the anterior face of the mesopleuron. The head increases allometrically with body size and the parallel inner orbits of the compound eyes in smaller individuals become slightly divergent below in larger individuals. The subquadrate appearance of the head in cephalic view is also emphasized in larger specimens. The males may be confused with C. pacifica, but distinguished by their smaller body size; more greenish-blue color; smaller and more widely spaced mesopleural punctures; broad rounded apical plate; long hairs on the basal, ventral edge of the femoral tooth; and the two median teeth on sternum 6.
C. sequoiae, like C. punctigena, is largely restricted in cismontane California to the Chaparral, California oakwoods, Mixed conifer forest, California steppe, and the ecotones, especially between the first two listed (figs. 6c, 25). Unlike the endemic C. punctigena, C. sequoiae is found northeastward in the western foothills of the Rocky Mountains. This distribution is within the range of plants of the genus Clarkia (Lewis and Lewis, 1955) on which the bee is oligolectic. This association with a host plant is unique among the small carpenter bees in North America; all others appear to be polylectic. The occurrence of this oligolectic species in cismontane vegetation types which are inhabited by 9—10 other species of Ceratina (table 1) suggests that specialization of food habits has contributed to its coexistence with other congeneric species. Combined measurements of samples throughout the range are: female wing lengths, 4.53 ± 033 mm, range 8.54.5 mm, n = 147; male wing lengths, 3.96 ± 0.29 nun, range 3.15—5.00 mm,
= 132. No phenetic-geographic segregates are apparent.
The nests are commonly found in Sambucus caerulea Raf., a native shrub. Eggs are placed on the surface of the loaf and slightly to the rear (figs. 31d, 311).