181 



HYDROPHIS. 



HYLACTES. 



163 



body is usually oval or rounded, convex above and flat beneath, or 

 nearly so : the tarsi are 5-jointed, and the mandibles bidentate. 



The principal genera of the family HydrophUidos may be thus 

 characterised : 



Genus Hydrous. Antennae with the terminal joint acuminated ; 

 sternum produced into an acute spine, which reaches considerably 

 beyond the insertion of the posterior pair of legs ; scutellum large ; 

 labrum entire ; tarsi of the four posterior legs compressed, and 

 furnished with bifid claws. The male sex has the anterior tarsus 

 dilated. 



Hydroiii piceui (Ifydrophilm piceus of the older authors) is one of 

 the largest beetles of this country, measuring about one inch and a 

 half in length. It is of a glossy black colour and oval form, convex 

 above and flat beneath, and has the elytra somewhat pointed at the 

 apex. This insect is not very uncommon in stagnant waters in 

 certain parts of England. It lives near the bottom of the water, 

 and may be said to walk rather than swim in that element. The 

 female insect deposits her eggs in a little nest composed of a gummy 

 substance, which is ejected from the abdomen, and in this nest the 

 eggs float until they are hatched. The larvae, which are of a lengthened 

 form and brownish colour, live in the water. 



Genus Hydrophilui (Leach). Labrum emarginated; mandibles 

 internally ciliated ; antennae with the terminal joint somewhat 

 obtuse and obliquely truncated; sternum terminating in a slightly 

 acute spine, which scarcely reaches beyond the insertion of the 

 posterior legs claws deutated at the base ; the anterior tarsi simple 

 in both sexes. 



Hydrophilia caraboida (Linnaeus), a common insect in some parts 

 of England, and like the species which is given as an illustration of 

 the preceding genus, lives in stagnant waters. Its farm is oval, 

 convex above, and flattened beneath ; and the elytra are rounded 

 posteriorly. It is of a glossy black colour, sometimes with a bluish 

 or violet hue, and about three-quarters of an inch in length. 



The genus Sjierckeu$ (Fabricius) is chiefly distinguished by the 

 antennae, which apparently are only 6-jointed ; the clypeus emargi- 

 nate ; the maxilla with the external lobe palpifonn : tibia smooth. 

 The body is very convex. 



Sperckeut emaryinatut (Fabricius) is about a quarter of an inch in 

 length, and of a brownish colour above and blackish beneath. It 

 lives in stagnant waters, and has been found adhering to the roots of 

 plants. As yet this has always been considered a very uncommon 

 insect in England. 



Genus Berotut (Germar). Eyes prominent; clypeus entire; appa- 

 rently 8-jointed, the terminal joint large and somewhat globular ; 

 thorax very convex ; the elytra broader thaa the thorax, and also 

 very convex ; posterior tarsi ciliated. 



Berottu luridiu (Stephens) is less than a quarter of an inch in 

 length, of an oval form, and grayish-yellow colour. The head is of 

 a brassy green colour, and there is a spot of the same hue on the 

 thorax. The elytra are striated. This species is common in ponds, 

 Ac. in various parts of England. 



Genus 1/ydrobius (Leach). Antenna; 9-jointed, the terminal joint 

 somewhat compressed and acuminated; clypeus entire; scutellum 

 small ; sternum simple ; eyes small and not prominent ; claws 

 simple. 



The species of this genus are usually of small size, of an oval or 

 rounded form, and always very convex. Like those of the preceding 

 genera, they live in ponds and ditches, and appear to prefer stagnant 

 waters. Mr. Stephens, in his ' Illustrations of British Entomology,' 

 enumerates 25 species. 



HYDROPHIS. [HYDRID*.] 



H YDROPHITE, a Mineral, a variety of Green Serpentine containing 

 vanadium. It occurs amorphous. Its fracture is irregular. The 

 colour is mountain green. Soft. Specific gravity 2 P 65. It is found 

 at Taberg in Smaland. The following is its analysis : 



Silica . 

 Oxide of Iron . 

 Oxide of Manganese 

 Magnesia . 

 Vanadic Acid 

 Water 



36-195 

 22729 



1-68 

 21-082 



0-115 

 16-080 



-97-SiJl 



HYDROPHYLLACE^E, Hydrophyli, a natural order of Exogenous 

 Plants, consisting of small trees, bushes, or herbaceous plants, often 

 hispid. The leaves are often lobed, alternate, or the lower ones 

 opposite. The flowers arranged in gyrate racemes or unilateral 

 spikes, or occasionally solitary and stalked in the axils of the leaves. 

 Calyx inferior, persistent, deeply 5-cleft, the recesses usually augmented 

 with reflexed appendages. Corolla monopetalous, hypogynous, regular, 

 shortly 5-cleft, between campanulate and rotate, rarely funnel-shaped. 

 Stamens 5, epipetalous, alternate with the segments of the corolla, 

 inflected in aestivation ; anthers versatile, 2-celled, the cells parallel, 

 dehiscing longitudinally. Ovary superior, simple, 1- or 2-celled, 

 style* 2, long ; stigmas 2, terminal ; placenUe 2, free at their back, 

 or united to the shell of the ovary, with two or many amphitropal 

 ovules on their inner face. Fruit capsular, 2-valved, sometimes 

 1-celled, with a large placenta filling the capsule, sometimes some- 



KAT OUT. DIV. VOL. III. 



what 2-celled, with the dissepiments incomplete. Seeds reticulated ; 

 albumen abundant, cartilaginous ; embryo conical, with its radicle 

 next the hilum. For many years it has been considered that 

 ffydroleacece was a distinct order from Hydrophyttacece, but recent 

 botanists recognise so little distinction between them, that they are 

 now both included in the above definition. Dr. Lindley places 



llydrophyllttm virghiicum, 



1, an entire flower; 2, the ovary; 3, a ripe seed-vessel; 4, a section of a 

 mature seed. 



Hydrophyllacea near Primulacece, Plumbaginacece, and Soraginacece. 

 Some of the species are cultivated in gardens for the sake of their 

 gay flowers, but none appear to possess useful qualities of any im- 

 portance. They are mostly found either in the north or south province., 

 of America, and are not known much beyond that continent. Nama, 

 and Hydrolea are found in the East Indies. In' the United States a 

 decoction of Hydrophyllum Canadense is one of the many remedies for 

 snake bites. Hydrolea is bitter, and the leaves are applied as a 

 poultice in India. 



Many of the species, especially those of the genera NemophUa and 

 EtUoca, are beautiful objects, and are extensively cultivated in our 

 gardens. There are 16 genera and 75 species. 



HYDROPHYLLUM. [HYDROPHYLLACM.] 



HYDROPIPER. [ELATINACE*;.] 



HYDROSAURUS. [IGUANIDJ;.] 



HYDROSTATICA. [ACALEPH*.] 



HYDROTALCITE, a Mineral, occurring massive, investing Steatite 

 in foliated masses. The colour is white. Streak the same, with a 

 pearly lustre. Transparent. It is flexible, with a soapy feel. Hard- 

 ness 2. It is found at Snarum. The following is its analysis : 



Magnesia 36-30 



Alumina 12'00 



' Peroxide of Iron 6'90 



Carbonic Acid 10-54 



Water 32.66 



Insoluble residue 1"20 



99-60 



HYDRUS. [HYDRIDE.] 

 HYLA. [AMPHIBIA.] 



HYLACTES, a genus of Birds established by Captain Philip 

 Parker King, R.N., for a form allied to Megapodius, with the following 

 characters : Bill sub-elongated, rather thin, with a sub-emarginate 

 apex ; nostrils basal, longitudinal, the membraue subtumesceut, and 

 covered with hairs down the middle. Wings very short, rounded ; 

 fifth quill longest. Tail sub-elongated, graduated. Feet strong ; 

 tarsi rather elongated, scutellated in front ; toes and claws elongated, 



