Larainae, LeConte, 1861

Archangelsky, M. & Manzo, V., 2006, The larva of Hydora annectens Spangler and Brown (Coleoptera: Elmidae, Larainae) and a key to New World Larainae larvae, Zootaxa 1204 (1), pp. 41-52 : 50-51

Key to larvae of New World Larainae *

Presently no unique characters will separate larvae of Elminae from those of Larainae . However, most mature larvae of Larainae are larger than the largest mature larvae of Elminae . Characters used in this key are based on last instar larvae, which can be recognized by the presence of spiracles on mesonotum and eight first abdominal segments, also they are more sclerotized and darker in color. This key has been modified and updated from ( Spangler and Santiago­Fragoso 1992; Springer and Rivas 2003). Material of the following genera was studied: Lara , Hydora , Pharceonus , Phanocerus , Hexanchorus and Pseudodisersus ; information on the remaining genera was obtained from the original descriptions.

1 Procoxal cavity closed ( Fig. 15 ).................................................................................... 2

­ Procoxal cavity open ( Fig. 16 ) ...................................................................................... 4

2 Lateral margins of thoracic and abdominal segments falcate ( Fig. 15 ) ........................ 3

­ Lateral margins not falcate ( Figs. 1–2 ). Southern Chile and Argentina.............. Hydora

3 Last abdominal segment elongate and deeply emarginated ( Figs. 17–18 ). Panama, Costa Rica, Colombia, Ecuador and Peru.................................................... Pharceonus

­ Last abdominal segment not elongate and feebly emarginated ( Fig. 15 ) USA, Mexico, Belize, Guatemala, Honduras, Costa Rica, Panama, West Indies, Colombia, Peru and Argentina..................................................................................................... Phanocerus

4 Sternopleural sclerites present on abdominal segments I–VI, I–VII or I–VIII ............ 5

­ Sternopleural sclerites present on abdominal segments I–V. Costa Rica, Panama and Ecuador.................................................................................................. Pseudodisersus

5 Sternopleural sclerites present on abdominal segments I–VI or I–VII; segments of tho­ rax or abdomen without or with disperse spines but never prominent spines along lateral margins ................................................................................................................... 6

­ Sternopleural sclerites present on abdominal I–VIII; lateral margins with prominent spines ( Fig. 21 ). USA.............................................................................................. Lara

6 Sternopleural sclerites present on abdominal segments I–VI, segment VII with may have a partial sternopleural suture................................................................................. 7

­ Sternopleural sclerites present on abdominal segments I–VII ...................................... 8

7 Apex of last abdominal segment rounded; abdominal tergum VIII with a pair of posterior tubercles ( Figs. 19–20 ); probasisternum broad. Length about 5 mm. Costa Rica, Panama, Guatemala, Mexico, West Indies, Ecuador, Brazil, Bolivia and Argentina...... .................................................................................................................... Hexanchorus

­ Apex of last abdominal segment emarginated; abdominal tergum VIII without posterior tubercles; abdominal terga I–VIII with 4 short longitudinal rows of seta­bearing tubercles; probasisternum long and broad. Length up to 15 mm. Guatemala, Costa Rica, Panama, Ecuador, Colombia and Peru..................................................... Disersus

8 Terga of thorax and abdomen without rows of tubercles; abdominal sternites I–VII subquadrate. Venezuela..................................................................................... Roraima

­ Terga of the thorax with 8, and abdominal segments I–VIII with 10, longitudinal rows of low tubercles bearing short ovoid setae; abdominal sternites I–VII subrectangular, 2x wider than long. Dominican Republic.................................................. Hispaniolara

Figures

FIGURES 15–21. Larainae larvae. Fig. 15, Phanocerus, ventral habitus; Fig. 16, Pseudodisersus, ventral habitus; 17–18, Pharceonus, abdominal segment IX, dorsal and ventral views; Figs. 19–20, Hexanchorus, abdominal segment IX, dorsal and ventral views; Fig. 21, Lara, first abdominal segment, dorsal view.

FIGURES 1–2. Hydora annectens. Dorsal and lateral habitus. Scale bar: 1 mm.