30 



ANNULOSA JAVANICA. 



Fam. 1. GYRINID^E. 



Degeer, in his immortal work, has observed, " Les Tourniquets approchent beaucoup des 

 Scarabes-'d'eau ou des Dytisques ;" but the remark was neglected by Latreille until lately. In 

 his Genera Crustaceorum et Insectorum he placed the Gyrini and Parni in the same family, 

 named by him Otiophori, thus confounding a relation of analogy with one of affinity. 



I know not whether I am quite right in considering these insects as belonging to the normal 

 groupe of Hydradephaga ; but certainly, both in their perfect and larva form, they are farther 

 distant from the Carabi than Dytiscus. As however it is imposible to proceed naturally in 

 a linear series of description, I begin with this Hydradephagous family, which is known to every 

 entomologist by its gregarious sportive nature and its auriform antennae. 



The larva? of Gyrinidee are exactly Scolopendrce in appearance, the tracheal brancbise 

 auswering to the false feet of the Chilopoda. The perfect insects are almost the only Hydra- 

 dephaga that possess a metallic lustre. 



Genus DINEUTUS Nobis. Gyrinus Lat. 

 Antenna brevissimae apice subacutas. 

 Labrum semicirculare hand eiliatum. 

 Palpi clavati. 



Pedes antici fere corporis longitudine. 

 Obs. These few characters, although merely external, will sufficiently separate this genus 

 from Gyrinus. M. Latreille has observed that, the exterior biarticulated lobe of the maxillae. 

 or (as it is more commonly called) the internal maxillary palpus becomes evanescent in the 

 exotic Gyrini, as well as in certain exotic genera of Geodephaga such as Therates. 



57. Politus, D. nigro-ceneus Icevissimus, clypeo nigro-piceo angidis rugosulis aureis, pedibws anticis piceis posticis 



pallidis. 



Long. corp. | 



Genus GYRINUS. 



58. Dentipennis, G. niger vix ceneus elytris postice unidentatis apice truncato-sinuatis piinctulatis substriatis. 



Long. corp. -fr + 

 Labrum nigrum. Corpus subtus nigro-aeneum vix cupreum ano hirsute Pedes antici picei posticis- 

 quatuor rufis. 



Obs. I am uncertain whether this species be sufficiently distinct from the Gyrinus Lulus of 

 the supplement to the Ent. Syst, a species which Fabricius afterwards abandoned in the Syst. 

 Eleutheratorum. 



59. Limbatus. G . elytris apice truncato-sinuatis striatis ad suturam tzneis, vitta medi& sub-ctiprea marginequt 



viridi. 



Long. corp. vix. iir. 

 Caput viride vertice subcupreo labrique margine viridi. $ Caput punctis duobus sub-impressis. 



Fam. 



