ANNULOSA JAVANICA. 35 



compose it, and which only again occurs in the contiguous family of HydrophiHdce. They 

 appear to lead naturally to Berosus, and such other genera of the next family. 



Fam. 4. HYDROPHILIDiE. 

 The analogy between the larger insects of this family composing the genu. Hydrous and 

 the larger Dytisci is too striking to escape the notice of the most cursory observer. 

 Their manners, their larvae, the singular dilatation at the extremity of the anterior tarsi of their 

 males may all serve to shew us how Linnaeus came to name the type of this family DuHscm 

 piceits. 



The most singular habit known of this insect is that the female spins out of her abdomen a 

 gummy matter, which forms an envelope for her eggs, and these, disposed symmetrically in 

 their oval receptacle, float about on the surface of the water until the larvae are hatched. 

 It is not known how many other genera of the family possess this curious economy. 



The insects of this family which come from tropical climates prove, by their near affinity to 

 European insects, how much fewer typical forms there are of aquatic insects than of terrestrial. 



Subgenus BEROSUS. Leach. 



69. Pvlchellus. B. griseo-Jlavescens, capite scutello thoracisque macula media divisa nigris, elytris striatis : 



maculis tribus. 



Long. corp. 1. 



Insectum supra pimctulatum. Elytra maculis tribus obscuris striisque nigris impressis, interstitiis crebre 

 punctatis, punctis nigricantibus. 



Obs. This genus often retains some of the metallic lustre of the Helophorida : 



Genus ENHYDRUS. Meg. 



70. Pallens. E. albicans nitidus punctulatus, thorace maculis quatuor obscuris transverse dispositis elytrisque 



obsolete striatis. 



Long. corp. s \. 



Genus SPERCHEUS. Fab. 



71. Platycephalus. S. infra nigricans, supra scabriuscidus cinereus, elytris lineis quatuor elevatis ; dorso 



bituberculato, pedibus subferrugineis. 



Long. corp. / 2 -. 



Obs. This curious little insect is truly a Spercheus, and thus becomes the second species of the 

 genus that is known to entomologists. 



Genus HYDROUS. Lin. Leach. 



72. Pallidipalpis. H. olivaceo-niger, elytris striis punctorum tribus, margineque vage punctulato. 



Long. corp. 1±-. 

 Hoc Insectum ab alio Americano (H. Fuscipalpe mihi) ex Insula Sanctae Trinitatis simillimo differt cor- 

 pore convexiore breviore, colore dilutiore, palpis crassioribus, et antennarum articulo sexto prseceden- 

 tibus simul sumptis multo breviore. 



F 2 73. Bilineatus. 



