Hydraenidae

Deler-Hernández, Albert & Delgado, Juan A., 2017, The Hydraenidae of Cuba (Insecta: Coleoptera) II: Morphology of preimaginal stages of six species and notes on their biology, Zootaxa 4238 (4), pp. 451-498 : 494

Key to the Cuban genera and species of Hydraenidae larvae

1. Urogomphi with the distance between their bases equal to or longer than the mid-width of their basal segment (URI). Urogomphal segment URII cup-shaped distally ( Fig. 6 e). Dorsal thoracic pores C4 absent ( Figs. 4 c; 7c; 9c). Mesothorax with setae of the posthypopleurites (Pohy 1) short ( Fig. 7 d).............................................. 2 ( Hydraena )

1’ Urogomphal bases of segments URI contiguous. Urogomphal segment URII evenly rounded distally ( Figs. 18 f; 27d). Dorsal thoracic pores C4 present ( Figs. 16 e; 20c; 22c; 25b; 27b). Mesothorax with setae of the posthypopleurites (Pohy 1) long ( Figs. 16 f; 22d)............................................................................................3

2. Antennal solenidium IIS2 of second and third instar larvae with a distal notch (Fig. 30b)............... H. guadelupensis

2’ Antennal solenidium IIS2 of second and third instar larvae evenly rounded, without a distal notch (Fig. 30a)........................................................................................ .. remaining species of Hydraena

3. Clypeus with two pointed projections at the level of setae Cl1 ( Figs. 22 a; 25a; 27a). Antennal solenidium IIS2 peg-like ( Fig. 23 e). Frontal area of head capsule of first instar with four egg-bursters ( Fig. 22 a)..... Ochthebius (a single species: attritus )

3’ Clypleus without pointed projections at the level of setae Cl1. Antennal solenidium IIS2 conical ( Fig. 17 e). Frontal area of head capsule of first instar with two egg-bursters......................... Gymnochthebius (a single species: fossatus )

Figures

FIGURE 4. Hydraena perkinsi, first instar larva: a, head capsule in dorsal view; b, head capsule in lateral view; c, pro- and mesonotum. Scale bar: 0.05 mm.

FIGURE 6. Hydraena perkinsi, first instar larva: a, abdominal segments I and II in dorsal view; b, same in ventral view; c, same in lateral view; d, abdominal segments VIII to X and pygopod in lateral view; e, left urogomphus in dorsal view; f, abdominal segments VIII to X and pygopod in dorsal view. Scale bar: 0.05 mm.

FIGURE 7. Hydraena perkinsi, second instar larva: a, head capsule in dorsal view; b, head capsule in lateral view; c pro- and mesothorax in dorsal view; d, same in ventral view; e, abdominal segments I and II in dorsal view; left urogomphus in dorsal view. CX: coxal cavities. Scale bar: 0.1 mm.

FIGURE 16. Gymnochthebius fossatus, first instar larva: a, head capsule in dorsal view; b, head capsule in lateral view; c, internal skeletal structures of head capsule in lateral view; d, same in dorsal view; e, pro- and mesothorax in dorsal view; f, same in ventral view. CX: coxal cavities. Scale bar: 0.05 mm.

FIGURE 17. Gymnochthebius fossatus, first instar larva. Mouthparts and antenna: a, labrum in dorsal view; b, labrum in ventral view; c, left mandible in dorsal view; d, right mandible in dorsal view; e, antenna; f, left maxilla in ventral view; g, left maxilla in dorsal view; h, labium in ventral view; i, hypopharynx. Scale bar: 0.05 mm.

FIGURE 18. Gymnochthebius fossatus, first instar larva: a, abdominal tergite I; b, abdominal tergite I and II; c, abdominal segments I and II in lateral view; d, abdominal segments VIII to X and pygopod in lateral view; e, same in ventral view; f, left urogomphus in dorsal view. Scale bar: 0.05 mm.

FIGURE 22. Ochthebius attritus, first instar larva: a, head capsule in dorsal view; b, same in lateral view; c, pro- and mesothorax in dorsal view; d, same in ventral view. CX: coxal cavities. Scale bar: 0.1 mm.

FIGURE 23. Ochthebius attritus, first instar larva. Mouthparts and antenna: a, labrum in dorsal view; b, labrum in ventral view; c, left mandible in dorsal view; d, right mandible in dorsal view; e, antenna; f, left maxilla in ventral view; g, left maxilla in dorsal view; h, labium in ventral view; i, hypopharynx. Scale bar: 0.05 mm.