HALIPLUS 



instance ; this Linnaeus named, with great propriety, 

 Haliotis imperforata. Leach also formed a genus, 

 which he named Padollus ; but these have all been 

 united by the modern French naturalists, who make 

 them merely sub-divisions of the Haliotis. These 

 molluscs inhabit the seas of all parts of the world, 

 and vary greatly in size, the writer of this article 

 having possessed them from the 10th of an inch to 18 

 inches in length. A number of the latter magnitude, 

 some years since, were brought to this country, it was 

 said from California ; but of late years no such large 

 examples have been imported from any country what- 

 ever. It is believed that no fossil examples of Halio- 

 tis have ever been discovered. The genus is ranked 

 in the second class, ParacephalophoTO, third order, 

 Scutibranchiata, first family, Otidea, in which the organs 

 of respiration are constantly situated on the animal's 

 left side. This genus might, doubtless, become more 

 clearly defined by an elaborate classification of its 

 species in their natural proximities ; but it would be 

 impossible to point out any thing more characteristi- 

 cally marked than these molluscs are from every 

 other known. 



HALIPLUS (Latreille). A genus of coleo- 

 pterous insects, belonging to the section Pcnlamera, 

 and family Dijtlcidcc, and distinguished from the other 

 genera of this family of water-beetles by having the 

 base of the hind legs covered by a large shield-like 

 plate composed of the dilated coxse of these organs ; 

 the palpi are also terminated by a minute conical 

 joint, in which respect they resemble the minute 

 species of Ecmlndndas (belonging to the adjoining 

 family Cardbidai), which are also sub-aquatic in their 

 habits, whence these insects have, by some systema- 

 tise, been considered as forming the point of con- 

 nection between the two groups. The species are 

 very numerous, of very small size, and may be con- 

 stantly observed swimming about with great agility 

 in almost every running or standing water ; the type 

 of this genus being the Huliplus clcvatus, which is at 

 once distinguished by the elevated lines upon the 

 elytra. 



"HALLERIA (Linnaeus). Ornamental green- 

 house shrubs, from the Cape of Good Hope. The 

 flowers are didynamous, and belong to the natural 

 order Scrophiilannecc. The plants grow freely in an 

 equal mixture of loam and moor-earth, and are propa- 

 gated by ripened cuttings in sand. 



HALL1A (Thunberg). A papilionaceous genus 

 of plants cultivated in the greenhouse, and succeeds 

 with the ordinary treatment thereof. 



HALORAGEJ^. A natural order, containing, 

 according to the Hortus Britannicus, seven genera, 

 and about twelve species, which, according to the 

 same authority, arc mostly obscure weeds, distin- 

 guished from OnagraricB by their naked and solitary 

 ovula. They are natives of moist places or ponds, in 

 various parts of Europe and North America. Some of 

 the species of Haloragis are tropical. They are not 

 known to possess any medicinal properties. 



HALORAGIS (Forster). A genus of small 

 New Zealand plants, belonging to Octandria Tetra- 

 , and to the natural order to which they give a 

 title. They require greenhouse management. 



HALTICA (Geoffrey). A very extensive genus 

 of minute coleopterous insects, belonging to the sec- 

 tion Tetmmcra, and family (Haleruc'ultc, distinguished 

 by the large size of the hind thighs, which enable the 

 nsects to leap about with great agility. They are 



HALTICA. 699 



for the most part ornamented and varied with brilliant 

 colours and shining bodies, and commit great havoc 

 upon the leaves of vegetables, both in the larva and 

 perfect states. The greatest number of species are, 

 however, found in South America, but these are for 

 the most part of a much larger size than those found 

 in our own country. From the extent of the genus 

 it has become necessary to subdivide it extensively. 

 Illiger did this in the Magazin dcr Entomologie, pro- 

 posing nine sections, which more recent authors, as 

 Latreille and Stephens, have regarded as so many 

 distinct genera. 



It is to this genus that the small insect belongs, 

 which is generally known under the name of the 

 Titrnip-jiy*, but which, as there are several hymeno- 

 pterous flies which likewise feed upon the turnip, it 

 would be more proper to distinguish as the turnip-flea, 

 naming it thus in allusion to its leaping agility. The 

 ravages of this minute insect upon this valuable plant 

 are unfortunately too well known to agriculturists to 

 need much description. The insect is indeed one 

 of the most formidable that can attack a crop. What 

 possibly can be more harassing to the fanner than to 

 see a fine thriving field of turnips just appearing in 

 leaf, destroyed in the course of a day or two by ene- 

 mies which are so minute as almost to escape detec- 

 tion, and so obscure in their habits, as up to the latest 

 moment to have escaped in this respect the observa- 

 tion even of practised observers of insects ? Whilst 

 doubting too whether his crop may possibly recover, 

 the unfortunate agriculturist may lose his season for 

 second sowing, or he may again encounter a similar 

 risk by resowing his land. Plans have been, and still 

 continue to be tried, with partial success, and in con- 

 sequence thereof they have been published to the world 

 as unerring remedies ; but so long as the real economy 

 of the creature remains unknown, it is impossible to 

 arrive at any other conclusion than that such success 

 has been obtained by chance, particular circumstances 

 of locality or season having produced effects which 

 have been attributed to some much more general 

 cause, but which have been found totally inapplica- 

 ble when those particular circumstances have ceased 

 to exist. 



Under these circumstances, the Doncagtcr Agricul- 

 tural Association, in 1830, proposed the turnip-fly aa 

 an advantageous subject of inquiry, and a series of 

 inquiries were issued, directed to numerous agricul- 

 turists and entomologists, seeking for information from 

 both relative to the subject. A great variety of in- 

 formation, of a very valuable nature, was thus ob- 

 tained, and from the published Report of this associa- 

 tion, the following particulars are concisely derived : 

 It appears that although the months of May and 

 June are stated as the period of the first attack, the 

 insects appear much earlier, and are ready to attack 

 the turnips first sown. It is evident, therefore, that 

 the beetles have previously undergone their prepara- 

 tory changes elsewhere than upon the turnip plant; 

 and this is an important fact, a point gained in the 



* This insect is systematically described under the name of 

 Htiltina nemnnim, Linnseus (by whom it was placed in the. 

 genus Cftryxomela) : it is of an oblong oval form, slightly depress 

 ed above, of a black colour, the elytra having a greenish tinge, 

 and each being ornamented with a broad longitudinal stripe of 

 a pale brimstone colour. It is about one-twelfth of an inch lonsr. 

 There are also several other species very nearly allied to it', hav- 

 ing similar habits, and being not les injurious, some of whieli 

 possess the pale stripe on the elytra, while in ethers it is want- 

 ing. They may all be distinguished by the thickened hind-leg's. 



