HALICTUS HALIOTIS. 



tree. They belong to Dodecandria, and the natural 

 order Styracineas. They are interesting shrubbery 

 plants, and are increased by layers or by cuttings of 

 the root. 



HALICTUS (Latreille). A genus of hymeno- 

 pterous insects, belonging to the section Aculcala, 

 sub-section Mellifera, or bees, and family Andremdce, 

 or short-tongued bees. The characters of this genus 

 will be found under the article ANDRENID^E ; but as 

 no account is there given of the economy of the spe- 

 cies of the genus, we will take this opportunity of 

 supplying the deficiency, chiefly from a valuable me- 

 moir, published in 1817, upon two of the species, by 

 the Baron Walckenaer, a celebrated French naturalist. 

 There is an extensive colony of one of the species esta- 

 blished at the foot of the wall of the barracks in the 

 turnpike-road near the entrance to Kensington palace, 

 where we have often noticed the insects. Never- 

 theless the species are solitary in their habits, the in- 

 dividuals having no tie upon each other, and the con- 

 gregation resulting merely from a convenient locality. 

 It is a curious circumstance, that it is only during the 

 night that the bees construct their nests, which con- 

 sist of a perpendicular passage, extending to a consi- 

 derable depth, and then branching off into several 

 other shorter passages, at the bottom of each of which 

 a mass of pollen paste is deposited with an egg, the 

 ball of the former being about the size of a pea, and 

 serving for the support of the larva when hatched. 

 During the day either the male or female bee re- 

 mains at the mouth of the burrow, in order to prevent 

 the entrance of enemies, such as cuckoo-flies (Tachi- 

 nte), and ichneumons, or ruby-tailed flies (Chrysidid&i). 

 On the return of its partner, which takes two or three 

 circular flights round the mouth of the burrow, the 

 sentinel immediately withdraws into the nest to make 

 way : moreover it is worthy of notice that, instead of 

 alighting upon any adjacent object, as is generally 

 the case with burrowing insects, the halicti fly at 

 once into the nests ; a circumstance attributed by 

 Walckenaer to the desire to elude their enemies, of 

 which there is a fearful catalogue, the most ferocious 

 being the Cerceris ornata, of whose habits we have 

 given an account under that genus. The preceding 

 observations relate to the Halictus terebrator of 

 Walckenaer, or the Melitta fulvo-cincta of Kirby, 

 one of the smallest species of the genus ; but in the 

 other species observed by Walckenaer, Halictus cca- 

 phosus, or the H. 6-cinctus of Latreille, which is one 

 of the largest of the species, the habits are different 

 in some respects, large, strong, and fearing but 

 little for the enemies which prey upon their smaller 

 brethren, this species works by day, and during 

 the greatest heat. The entrance to the burrows is 

 large enough to admit two individuals at once, where- 

 as in the other species it is only of the size of the 

 head of the insect. The direction of the burrow is 

 also different, and, instead of diverging into several 

 channels, it terminates in a large round cell, two 

 inches and a half in diameter and three inches high, 

 filled with earthen cocoons, attached loosely together, 

 leaving various channels between them. When 

 examined, it is found to consist of about a score of 

 earthen cocoons, each having the mouth closed, so 

 that the enclosed inhabitant has no communication 

 with the external air. The inner walls of the cocoons 

 are finely polished. 



HALlMODENDRON (Fischer). This genus 

 of plants was formerly called Robinia by Linnaeus and 



Heritier, and Caragana by Lambert : but finally de- 

 scribed and renamed by Fischer. It belongs to Legu- 

 mi no.10!, and forms a pretty shrub in flower borders : 

 may be increased by seed or by grafting on the t'ara- 

 gajia arborescens. The plants are natives of Siberia, 

 and are there called salt or sea trees. 



HALIOTIS (Linnaeus, and modern authors). 

 This well-known but elegant mollusc constitutes a, 

 well-defined genu, numerous in species, and remark- 

 able for their ear-like form, whence the derivation of 

 their name, sea-ear. As this shell is to be met with 

 in every collection, a minute description of it, in 

 scientific language, would here be useless ; we will, 

 nevertheless, give its general characters. The sub- 

 stance of the shell is internally brilliantly nacreous ; 

 it is extremely depressed, more or less of an oval 

 shape, with a very small spiral termination, and very 

 flat. The aperture is the full size of the shell ; 

 its edges continuous, the right one thin and tren- 

 chant, the left flattened, enlarged and sharp, parallel 

 to the left side ; a series of holes exist, which 

 serve for the passage of the two-pointed lobes 

 of the animal's mantle. There is only one great 

 muscular impression. The animal is entirely cr- 

 vered by its shell. As the increase of the animal's 

 size requires an extension of its protecting covering, 

 a new hole is commenced, appearing at first only a 

 notch on the margin, afterwards completed as the 

 growth of the shell continues, and others are formed 

 in succession, while the perforation nearest the spire 

 is carefully closed in the same succession, leaving, 

 however, in almost every instance, six holes at the 

 same time open. When the animal is at rest it ad- 

 heres, like the patella, to the rock or substance on 

 which it is found, and can only be detached by a sud- 

 den effort, as they have resisted the application of a 

 lever, till every portion of their shell was so far 

 broken as no longer to furnish a point of resistance. 

 An ingenious naturalist has calculated that it would 

 require at least a ton weight to force these shells 

 from their resting place, could the substance of them 

 withstand the application of the necessary mechanism, 

 such is the perfect vacuum formed by the animal. 

 There are probably few of our readers who, in the 

 early part of life's dream, have not witnessed this 

 philosophical fact by the simple application of a pirce 

 of wet leather to any heavy substance ; as the subject, 

 however, is most ably explained in the First Division 

 of this work, we need not here go into it, but pr<- 

 ceed with a description of the animal constructing 

 the haliotis. Its body is of a very depressed oval 

 shape, slightly spiral backward ; it is provided with 

 a large foot, doubly fringed round its circumference ; 

 the head flattened, tentacula conical at the base, and 

 a little flattened ; the eyes are placed at the summit 

 of prismatic peduncles, situated on the external edge 

 of the tentacula ; the mantle is very thin, deeply 

 divided on the left side ; the two-pointed lobes form, 

 by their junction, a canal to conduct water into the 

 bronchial cavity, situated on the left side, and inclos- 

 ing two very long, unequal, bronchial combs. These 

 molluscs adhere to rocks nearly on a level with the 

 sea, and, during the fine summer nights, wander to 

 feed on the herbaceous plants that grow near the 

 shore. Their flesh is considered good eating, and in 

 Guernsey they are sold in the market in common 

 with other shell-fish. Larnarck sub-divided this 

 genus, separating from it those species which were 

 imperforate (or without holes) ; his Slowatia is an 



