MELON. 



MEMBRANE. 



78 



tl. motpmonu, a common insect in some puts of North America, 

 U about three-eighths of an inch in length ; the head and thorax are 

 black, but covered with minute yellow *oale* ; the elytra are of a 

 yeUowuh brown-colour, also covered with yellow scales ; the under 

 parU of the body are nearly white, owing to the dense clothing of 

 scale* with which they are furnished ; the legs are deep-yellow, and 

 the tani are black. About seven other species of the present genus 

 arc known, nearly all of which inhabit South America. 



Difkuctpkaia (Dejean). The species of this genus are confined to 

 Australia. [DU-HUCEPHALA.] 



Pltctrit (LepeL and Serr.). The claws of the intermediate tarsi 

 unequal in sue ; the larger of these two pairs of claws are bifid, and 

 all the claws of the remaining tani are also bifid. Twelve species are 

 known ; they inhabit Brazil 



Ctnupu (LepeL and Serv.) The species of this genus, all of which 

 inhabit Brazil, may be distinguished by having two small notches near 

 the middle of the hinder margin of the thorax ; the space between 

 the notches is received into a notch in the scutellum. The antenna] 

 are 10-jointed : the claws of all the tarsi, with the exception of the 

 anterior pair, are unequal ; the larger claw of the intermediate tarsi 

 is entire in the male sex, the other claws are bifid. In the females all 

 the claws are bifid. The body is covered with minute scales, and is of 

 an elongated form. 



Artoda (Leach). Antenna) 10-jointed; sternum produced an- 

 teriorly ; the claws of the tarsi unequal in the male sex, and equal in 

 the females. The larger claws of the males are bifid. The basal joints 

 of the tarsi are short, and the terminal joint is very large, and grooved 

 beneath. These insects are of large size, and adorned with brilliant 

 colours. In the form of the sternum, and structure of the tarsi and 

 daws, they depart from the true M dolonthula, and evince an affinity 

 to the Ruldida and Anojiloynalhi, where, as in the present genus, the 

 species have the power of folding the claws backwards against the 

 under side of the terminal joint of the tarsus (like the closing of the 

 blade of a penknife) ; and when thus closed the point of the larger 

 claws is lodged between the penultimate and antepenultimate joints 

 of the tarsi 



A. laniytra, a common species in some parts of North America, is 

 rather more than three-fourths of an inch in length, of an oval form, 

 and pale yellow-colour, with green reflections : the under parts of 

 the body are of a dark green-colour, and thickly furnished with 

 white hairs. 



There are six other known species of this genus : one is found in 

 Guadeloupe, and the remainder inhabit South America. 

 MELON, rCucuius.] 



MELO'PHUS (Swainson), a sub-genus of Leptonyx (Sw.). It is thus 

 characterised : General structure of Fringillaria, but the upper man- 

 dible U notched near its tip. Hinder claw lengthened, but rather 

 shorter than its toe. Lateral toes equal. Tail even. Head crested. 

 Tertials not lengthened. (Sw.) Ex. M. erythroplcrtu. (' 111. of Orn.,' 

 I>l. 132.) [KKIXUILLIDJL] 



MELt iSIKE.K, a family of IHatomacta, formed by Kutzing. The 

 specie* an striated, not having a central opening on the secondary 

 side. The stria; are interrupted in the median line. It includes the 

 genera (jallionella, Melotira, Podotira, and others. Meneghiui, in his 

 ' Natural History of Diatomeec,' makes the following critical remarks 

 on this group : 



" The Mclorirtr in general may be regarded as polypariform associa- 

 tions of C'ydottlUr, and the comparison prevails principally in the second 

 sub-genus. The distinction of the two sub-genera is also proposed by 

 Hassmll (SpharoplUH-a, Mdotrira) ; but it is to Kutzing we are indebted 

 for establishing it upon the important character of the carina, which 

 occurs only in the first two species (.I/, talina, M. numuiuioidet), a cha- 

 racter on whose organographic value we cannot decide anything, but 

 which merits some consideration in a morphological point of view : 

 for that projecting ring bounds the lateral surfaces; whilst in the 

 other specie*, with sides more or less convex, these are continuous, 

 as it were, with the primary surfaces. In all the species we may 

 notice the double furrow which forms a ring connecting the body of 

 each individual laterally to the interrtitial ring ; this furrow or canal 

 prcnU apertures dupoeed in a regular manner. Kutzing believes 

 the** supposed apertures to be sections of the canals themselves, that 

 is, portions of them seen in projection. Thin opinion is the only one 

 consistent with the fact that the filament being cylindrical, and there- 

 fore presenting itself indifferently on every side, these apparent aper- 

 ture* are always seen arranged near the margin. Kbrenberg's assertion 

 that they are more numerous in some species, does not seem to be 

 confirmed. This appearance is still more complicated, inasmuch as 

 these fine tubular canals project from the internal surface of the 

 shield, and a slight furrow externally corresponds with them. This 

 condition is eviilrnt in ifrlorira distant, in which, owing to the greater 

 depth of the furruw, the apparent perforations remain separated from 

 the margin. The interstitial ring present* peculiarities uf which we 

 have no instance in the preceding genera. Its tenuity and the great 

 variety <>f it* extension are important characters. But here we must 

 add the very important one of the changes it undergoes during 

 observation. It is not uncommon to see the two halves of the articu- 

 lation Mpareto themselves slowly, and enlarge at the same time with 

 the rug. This fact a not decisive in respect to the great question of 



the animal nature of these beings ; for it is not subject to a subse- 

 quent contraction, and because in plants wo have the analogy of 

 *l>iroffynr, in which, on the rupture of the outer tube, the extremities 

 of the articulation, which were inflected like the finger of a glove, 

 expand themselves as if by elasticity ; but many facts controvert this 

 inference. In support of the opposite opinion U the frequent enlarge- 

 ment of a particular articulation, in a manner similar to that of the 

 (Kduyoaia. But llmsill justly observe*, ' for this eudochrome . . . 

 never become* condensed into a distinct organ or sporangium. 

 this reason, the resemblance is reduced to a mere appearance. As to 

 this supposed endochrome, proofs are certainly wanting that it is an 

 ovary, as Ehrenberg supposes ; but they are alto wanting to show that 

 it consists of gum, starch, or chlorophyll, which would be necessary 

 were it a goniinic substance, as advanced by Kutzing ; and analogy 

 even is wanting, for we do not see in any Alya a similar disposition of 

 the internal substance. The often-quoted resemblance to the Con- 

 ferra cannot even be deemed apparent ; for in no Conferra are distinct 

 spherules met so regularly, or disposed so symmetrically. During 

 desiccation it happens in the marine species, as in the Podotira already 

 described, that the internal substance adheres to the inner wall in the 

 form of oily globules surrounded by a distinct transparent margin, 

 and compressed one against another in the form of regular polygons. 

 Ehrenberg also speaks of diaphanous vesicular spaces, which he regards 

 as stomachs. Kutzing enumerates, figures, and describes nineteen 

 species, marine, freshwater, and fossil, besides the four doubtful ones 

 placed at the end, and the famous Ferruyinea (if. ochracca, Haifa), 

 which he proves not to belong to the class of liiatomtue. 



" We shall find, as a character common to them all, the circular 

 figure of the vertical section parallel to the lateral surfaces; a charac- 

 ter which, as well as the other, of a radiated disposition of the stria 

 upon the lateral surfaces, we shall find repeated in the family of 

 Cotcinodiicctr, which, having the shield of a cellular structure, belong 

 to the tribe of Areolatte. Perhaps we may suspect some Mdorira 

 (tulcata, decuttala, lirata) to be furnished with the same organic 

 condition, and hence arises a fresh doubt respecting the systematic 

 value that has been ascribed to it. 



" In general we may also say, that in the Xelorirtte the development 

 of the lateral surfaces prevails over that of the primary ones, which 

 we find finally to disappear in certain genera (1'tj.ridicula, Podotira), 

 as well as in some species of Mdutira (variant, orichalna), the 

 increased length of the articulations involving the corresponding 

 development of the primary surfaces : and it is to be observed, that 

 although in this family the primary surfaces differ precisely as much 

 in form as they do in the three preceding ones, yet we find in these 

 the same organic character as in the greater number of the other 

 genera, namely, the presence of longitudinal furrows or canals. The 

 separation of one lateral surface or valve from the other, with tho 

 consequent dilatation of superficies, which the primary surfaces exhibit 

 before the duplication takes place (though verified to some degree in 

 other genera, yet in the Melorira better than elsewhere), present* an 

 undeniable analogy with the reduplication of Detmidior, which 

 Brcbisson distinguishes from the deduplication of Diatomea. The 

 particular disposition of the internal substance, the currents or mucous 

 threads radiating from a centre, the enlargement of some articulations, 

 and the dilatation of the interstitial ring, are isolated facts, which 

 however merit particular attention in the paucity of our knowledge." 



[DlATOMACB*.] 



ME'LYRIS, a genus of Coleopterous Insects established by Fabri- 

 ctua for tho reception of certain species of the Linneoan genera 

 Can/liarit and Dcrmutet. It belongs to the family f^rricornct of 

 Latreille, and constitutes the type of the family Melyridrr. The 

 Mdyridte are active and often gaily-coloured little beetles, usually 

 found on flowers, which they frequent for the purpose of preying on 

 other insects. They have soft, oblong, or ovate depressed bodies ; 

 short filiform pointed palpi; exserted heads; dentntcd mandibles; 

 and usually filiform and serrated antenna;. Some of the s|cies of 

 JUafifliitu, a genus of Melyridac found in Britain, are furnished with 

 red bladder-like appendages at the anterior angles of the thorax and 

 base of the abdomen, capable of being contracted or dilated at tho 

 will of the insect, and usually exhibited when it is alarmed. 

 Mr. Westwood regards these bodies ns portions of an apparatus for 

 emitting an olleusivo effluvium, and Curtis as means of enabling the 

 insect to increase or decrease its gravity during flight The larva), as 

 well as the perfect insects, are carnivorous. The family is interme- 

 diate between the Tdephorida and Cltridcc. The genera Malachiut, 

 Datylet, Enicopm, Dolichoroma, and Aplocntmut contain British species. 

 (Westwood, Modern Clawiftcation of IntecU.) 



MKMBKANE (in Anatomy) is an expansion of any tissue in a thin 

 and wide layer. Since the time of Bichat [BICHAT, in Bioo. Div.] the 

 membranes have been generally enumerated as of three kinds, the 

 serous, tho mucous, and the fibrous, which are distinguished as well 

 I'V thrir physical characters and their functions, as by the diseases to 

 which each is peculiarly subject. 



The Serous Membranes are so named from the character of their 

 secretion, which consists of a very small quantity of thin serous fluid. 

 In the adult condition of man and tho higher vcrtebrata, they form 

 what are called shut sacs. In each of the cavities of the chest, for 

 example, which are exactly filled by the lungs, there is a serous 



