Hylaeus, Fabricius, 1793

Chen, Xuan & Xu, Huanli, 2009, A key to species of the genus Hylaeus (Hymenoptera: Colletidae) from mainland of China with descriptions of new species and new records, Zootaxa 1974, pp. 31-50 : 32-35

Key to species of genus Hylaeus from mainland of China

Key to subgenera of Hylaeus based on Dathe (1980, 2000). Male is unknown for H. medialis Morawitz and female is unknown for H. sinensis Dathe.

Males

1. Dorsal carinae of the two penis valves in dorsal view parallel and in close contact to their apex ( Fig. 1), or, if separated, then only narrowly so (outline of the two penis valves together cuneiform to spindle-shaped).....................................................................................................................................................................2

- Dorsal carinae of penis valves in dorsal view in contact basally but clearly diverging near base or near midlength, often abruptly bent laterad ( Fig. 8)..........................................................................................16

2. Apical lobe of S7 simple with smooth margin, hairs absent or sparse and confined to lateral part of proximal lobe; scape usually slender; labrum and mandible frequently with yellow spots [subgenus H. (Paraprosopis) Popov]..........................................................................................................................................3

- Apical lobe of S7 pectinate ( Fig. 2); scape commonly conically dilated or flattened, but if slender, then sternal callosity on S3 or lateral fringe of T1 absent; labrum and mandible black [subgenus H. ( Hylaeus ) Fabricius].....................................................................................................................................................4

3. Middle of frons (above antennal sockets) smooth, shiny; scape conspicuously broadened, hairs on scape long; marks on pronotal collar yellow ............................................ H. (Paraprosopis) concinnus Cockerell

- Middle of frons punctate; scape slightly broadened, hairs on scape very short or absent; pronotal collar black........................................................................................... H. (Paraprosopis) nigricallosus Morawitz

4. Apical half of gonoforceps short, its apex with distinct process curved medially ( Fig. 1); gonobase long, conical; genitalia large......................................................................... H. (Hylaeus) difformis (Eversmann)

- Gonoforceps normal; gonobase short; genitalia small.................................................................................5

5. Scutum with two white marks ............................................................. H. (Hylaeus) przewalskyi Morawitz

- Scutum wholly black...................................................................................................................................6

6. Scape wholly black, slightly broadened......................................................................................................7

- Mark on scape white or yellow, normal or broadened...............................................................................10

7. Marks on lateral face, supraclypeal area, pronotal collar and tegula white or yellow.................................8

- Lateral face, supraclypeal area, pronotal collar and tegula black................................................................9

8. Middle of frons shiny and smooth; marks on body white; marks on paraocular area extending beyond the level of the upper margin of the antennal socket, supraclypeal area white. .................................................. ................................................................................................................... H. (Hylaeus) potanini Morawitz

- Middle of frons punctate; marks on body yellow; marks on paraocular area not reaching level of the lower margin of the antennal socket; lower portion of supraclypeal area yellow, upper portion of it black........... ....................................................................................................................... H. (Hylaeus) paulus Bridwell

9. Basal spot on hind tibia yellow, small and obscure; S7 normal ( Fig. 2); apex of S8 bilobate ...................... .......................................................................................................................... H. (Hylaeus) sinensis Dathe

- Hind tibia wholly black; apical lobe of S7 elongate ( Fig. 3); apex of S8 not bilobate.................................. ......................................................................................................................... H. (Hylaeus) niger Bridwell

10. Malar area elongate, square or length slightly shorter than width H. (Hylaeus) dolichocephalus Morawitz

- Malar area very short, nearly linear...........................................................................................................11

11. Middle of face (portion below and beside antennal socket) deeply concave ....... H. (Hylaeus) dorni Dathe

- Middle of face flat......................................................................................................................................12

12. Scape not broadened; body small, its length commonly less than 4 mm ...................................................... .............................................................................................................. H. (Hylaeus) fuliginosus (Warncke)

- Scape broadened; body length commonly over 4 mm ...............................................................................13

13. Inner eye margin with a conspicuous line of hairs; hair-bands on apical half of metasomal terga wide, dense, but medially interrupted............................................................. H. (Hylaeus) mongolicus Morawitz

- Inner margin of eye without hair line; hairs on metasomal terga short, fine and sparse, not forming hairbands..........................................................................................................................................................14

14. Ratio between head length: width more than one........................................ H. (Hylaeus) sibiricus (Strand)

- Ratio between head length: width less than one........................................................................................15

15. Marks on body white, penis valves obviously exceeding gonoforceps H. (Hylaeus) asiaticus (Dalla Torre)

- Marks on body yellow, penis valves subequal or slightly exceeding gonoforceps ....................................... .................................................................................................................. H. (Hylaeus) perforatus (Smith)

16. S8 with prolonged basal part and apical process, the latter with short hairs or hairless and hooked downward; scape broadened, shield-like; paraocular area lacking transverse flat impressions............................. ............................................................................................................ H. (Lambdopsis) pfankuchi (Alfken)

- S8 more or less rhombiform, with short basal and apical parts, or apical process, if elongated, then with hairs and not hooked; S6 rounded or emarginated; scape slender or conically enlarged, or if scutiform, then face with flat transverse impressions on paraocular area and below antennal socket.......................17

17. Penis valves in dorsal view gently bent so that between them can be seen a pair of acute or truncate spines, these being ventral projections of penis valves ............................................... H. (Dentigera) luna sp. nov.

- Penis valves in dorsal view largely approximate, no spines thus visible from above between penis valves, ventral projections usually short and broad, not spine-like.......................................................................18

18. S8 with extremely elongated, curved, slender apical process, its apex with pair of hair tufts ( Fig. 4); S6 emarginate in middle; thorax, particularly mesepisterna, strikingly coarsely and strongly punctuate; S7 with apical lobe reduced, slender, pointed, with sparse hairs................. H. (Nesoprosopis) floralis (Smith)

- S8 rhombic, with short, rounded or truncate, hairless apical process; S6 not emarginated; thorax usually finely punctuate; S7 with apical lobe reduced, compact, with hairs that may be short and sparse [subgenus H. ( Prosopis ) Fabricius]............................................................................................................................19

19. Scape slender ............................................................................................ H. (Prosopis) confusus Nylander

- Scape coniform ................................................................................... H. (Prosopis) variegatus (Fabricius)

Females

1. Mandible tridentate......................................................................................................................................2

- Mandible with two teeth or apex bilobate...................................................................................................4

2. Marks on paraocular area often elongate, contiguous with inner orbit ........... H. (Dentigera) luna sp. nov.

- Face entirely black [subgenus H. (Lambdopsis) Popov].............................................................................3

3. Underside of flagellum brown, upper width of clypeus: maximum clypeal width more than 0.5 ................ ............................................................................................................. H. (Lambdopsis) medialis Morawitz

- Underside of flagellum yellow, upper width of clypeus: maximum clypeal width less than 0.5.................. ............................................................................................................ H. (Lambdopsis) pfankuchi (Alfken)

4. Facial fovea elongate, somewhat surpassing upper ocular margin, converging strongly toward ocelli, terminating closer to ocelli than to eye ( Fig. 5) [subgenus H. (Paraprosopis) Popov]...................................5

- Facial fovea short and straight, barely reaching upper ocular margin and terminating closer to eye than to ocelli ( Fig. 6)...............................................................................................................................................6

5. Marks on pronotal collar and pronotal lobe yellow; punctures on mesopleuron sparser than those on mesoscutum ............................................................................... H. (Paraprosopis) nigricallosus Morawitz

- Pronotal collar and pronotal lobe wholly black; punctures on mesopleuron like those on mesoscutum ...... ........................................................................................................ H. (Paraprosopis) concinnus Cockerell

6. Mesepisternum with strikingly coarse and strong but regular pitlike punctures; T1 without lateral fringe.. ........ ........................................................................................................ H. (Nesoprosopis) floralis (Smith)

- Mesepisternum with fine punctures or, if coarse and strong, then not regular and metasomal terga densely punctuates; T1 often with lateral fringe.......................................................................................................7

7. Larger species (body length 5–9mm) usually with short head; facial fovea usually with upper end well separated from eye; propodeum short, at least lateral and posterior surfaces mostly rounded, not delimited by carinae, with fine sculpture and covered with white feltlike hairs; T1 often with lateral fringe of white hairs, but if fringe absent, then metasomal base sometimes red [subgenus H. ( Prosopis ) Fabricius].........8

- Smaller species (body length 3.5–8.0mm) with elongated head; facial fovea shorter, upper end close to eye margin; propodeum usually sharp-edged or with carina around posterior surface; metasoma black, usually without lateral fringe on T1, but if T1 has fringe, then mesepisternum densely, finely punctuate and propodeum rounded, with fine sculpture [subgenus H. ( Hylaeus ) Fabricius]......................................9

8. Metasomal base black............................................................................... H. (Prosopis) confusus Nylander

- Metasomal base red ............................................................................ H. (Prosopis) variegatus (Fabricius)

9. Preoccipital ridge very sharp ............................................................... H. (Hylaeus) difformis (Eversmann)

- Preoccipital ridge absent............................................................................................................................10

10. Scutellum with two spots; T1 and T2 often red................................... H. (Hylaeus) przewalskyi Morawitz

- Scutellum; T1 and T2 wholly black...........................................................................................................11

11. Face wholly black ............................................................................................ H. (Hylaeus) niger Bridwell

- Marks on face yellow or white..................................................................................................................12

12. Malar area elongate....................................................................... H. (Hylaeus) dolichocephalus Morawitz

- Malar area very short, nearly linear...........................................................................................................13

13. Hair-bands on apical half of metasomal terga wide, dense but interrupted in middle................................... .............................................................................................................. H. (Hylaeus) mongolicus Morawitz

- Hairs on metasomal terga short, fine and sparse, not forming hair-bands.................................................14

14. Marks on clypeus yellow or white.............................................................................................................15

- Clypeus commonly wholly black..............................................................................................................16

15. Two small spots on clypeus, marks on paraocular area drip-like; apical marginal zones of T2 to T6 brownish black ....................................................................................................... H. (Hylaeus) sibiricus (Strand)

- A longitudinal stripe on clypeus, marks on paraocular area well developed; apical marginal zones of T2 to T6 wide and bright............................................................................... H. (Hylaeus) asiaticus (Dalla Torre)

16. Marks on paraocular area strip-shaped, along eye margin........................................................................17

- Marks on paraocular area triangular, subtriangular or irregular................................................................18

17. Body length commonly less than 5mm; 1FL: 1FW less than one; pronotum wholly black ......................... ....................................................................................................................... H. (Hylaeus) paulus Bridwell

- Body length commonly over 6mm; 1FL: 1FW more than one; marks on pronotum yellow ........................ .............................................................................................................................. H. (Hylaeus) dorni Dathe

18. Marks on paraocular area not reaching the level of the lower margin of the antennal socket ...................... .............................................................................................................. H. (Hylaeus) fuliginosus (Warncke)

- Marks on paraocular area reaching the level of the lower margin of the antennal socket or extending above it.................................................................................................................................................................19

19. Head length: head width less than one; marks on paraocular area clearly extending above the level of the lower margin of the antennal socket; white apical spot of hind tibia inconspicuous .................................... ................................................................................................................... H. (Hylaeus) potanini Morawitz

- Head length: head width more than one; marks on paraocular area reaching the level of the lower margin of the antennal socket but not above it; apex of hind tibia black .............. H. (Hylaeus) perforatus (Smith)