29-2 



D I S P E II I S D I V E R. 



in front of the disk formed by ihe pectorals. Their 

 bones are soft, and their skin viscous and without 

 scales ; but it is sprinkled with minute grains of a hard 

 substance. Their stomachs are very large, their 

 intestines long and abundantly furnished with caeca, 

 characters which indicate habits very different from 

 the former genus, with which they have sometimes 

 been confounded. 



DISPERIS (Swartz). An orchideous genus from 

 South Africa, which succeeds, if potted, or planted in 

 a pit in compost made of a mixture of loam and peat 

 earth. 



D1SPORUM (Salisbury). A genus of perennial 

 herbs from China and Nepal. Class and order Hex- 

 andria Monogynia, and natural order Melanthacece. 

 Generic character : corolla of six petals, bell-shaped, 

 nectariferous holes at the base of the segments ; sta- 

 mens under the germen ; filaments very short ; style 

 abbreviated ; stigmas three-capsuled, three-valved ; 

 seeds membranous. According to Sweet, these 

 plants are hardy enough to stand on a warm border, 

 if sufficiently defended from frost. 



DIURIS (Smith). A genus of curious plants from 

 New Holland, belonging- to the natural order Orc/ii- 

 dece. They are much easier cultivated than the 

 South American species of the same order ; only 

 requiring to be potted in moor-earthy soil, and kept 

 in a pit or green- house safe from frost. 



DIURNA (Latreille). A section of lepidopterous 

 insects, corresponding with the Linnaean genus Papilio, 

 or butterflies, being distinguished by having the mar- 

 gin of lower wings not furnished at the base with a 

 scaly bristle for retaining the upper wings in their 

 proper situations, these, as well as the second pair, be- 

 ing generally perpendicularly elevated during repose ; 

 the antenna? are generally terminated by a club, and 

 the larvae have sixteen legs. The perfect insect, always 

 furnished with a spiral tongue, flies by day, and the 

 under surface of the wings is not less beautifully varie- 

 gated than the upper. Having, under the article BUT- 

 TERFLY, entered at length into the natural history of 

 these beautiful insects, we shall here simply give a 

 slight sketch of their distribution into groups, esta- 

 blished upon their diversities of structure. 



Fam. 1. Papilionidcz. Anterior legs not abbre- 

 viated, fit for walking, alike in both sexes. Pupa 

 angulated, suspended, and braced across the 

 middle. Antenna? not hooked at the tip. Here 

 belong the genera Pujrilio, Zelima, Parnassius, 

 Thais, Picris, Pontia, Colins. 



Fam. "1. NymphaMee. Anterior legs abbreviated, 

 not fitted for walking ; ungues bifid ; pupa 

 angulated, and merely suspended by the tail ; 

 middle cell of the lower wings closed. Genera : 

 Cetfwsia, Argynnis, Melittea, Vanessa, Libyihea, 

 Biblis, Nymphalis, &c. 



Fam. 3. HdiconMce. Pupa smooth, suspended 

 only by the' tail ; anterior legs imperfect ; dis- 

 cordal cell sometimes open. Danais, Heliconia, 

 Acreea, &c. 



Fam. 4. Lyccenidce. Anterior legs semi-abbre- 

 viated ; claws minute ; pupa smooth, braced, 

 larva onisciform. Genera . Polyommatus, 

 Tkecla, &c. 



Fam. 5. Hesperiid<. Anterior legs not abbre- 

 viated ; antennas hooked at the tips ; pupa 

 smooth, braced, and folliculated. Genera : 

 Hespcria, Thymelc, &c. 

 These characters, it will be seen, are in some degree 



derived from the preparatory stages of the insects ; 

 indeed, these considerations afford much more import- 

 ant clues to the classification of insects than thev were 

 imagined to possess by the earlier authors upon this 

 branch of natural history. Of those who adopted a 

 contrary opinion, Schrank may especially be noticed. 

 He consulted metamorphosis in its various modifica- 

 tions, in his arrangement, and on its importance as a 

 guide to minor sub-divisions, he has the following in- 

 genious observations, quoted by Dr. Horsfield in his 

 Lepidoptera Javanica : " Metamorphosis, in its larva 

 state, may, and I think must be taken into the charac- 

 ters of the genus, in the absence of other sufficiently 

 distinctive notices. Those botanists who have derived 

 their systems primarily from the fruit, have neverthe- 

 less a regard for the flower, and by this means recipro- 

 cally elucidate existing obscurities. Caterpillars are 

 the flowers of the lepidoptera. They are, indeed, not 

 always present when the perfect insects are before the 

 examiner. But is the case different with the botanist:*" 

 And Mr. MacLeay says to the same effect : "As the 

 knowledge of the whole life of an insect must make 

 us better acquainted with its nature than a mere 

 description of one of its forms, in the same proportion 

 ought metamorphosis to outweigh every other prin- 

 ciple of arrangement." 



DIVER Colymbus. A genus of web-footed birds, 

 and one of the most aquatic of the whole order. 

 They appear in structure and in habits as literally 

 made for the water, and the water only ; and they 

 have equal command of themselves on and under the 

 surface of that element. They are chiefly natives of 

 the northern hemisphere, and of the more northerly 

 seas, being birds peculiarly fitted for contending with 

 the storm in the water itself, and probably getting to 

 a greater depth than that to which the water is dis- 

 turbed by the waves. They are especially abundant 

 about projecting headlands in the northern countries, 

 where the current runs strong, and the surf and spray 

 occasionally beat with great violence. But amid the 

 turmoil of the storm, the divers appear as much at 

 home in the foaming water as the small birds do in 

 the groves on the gentlest morning of May. In such 

 situations they may be seen driving about, now appear- 

 ing in the trough of the waves, now boring through 

 the ridges, now on the wing for a little space, but 

 anon plunging into the water. At such times and 

 in such places the fry of fishes, which remain and 

 feed much nearer the surface than stich as are full 

 grown, are collected in abundance, and many of them 

 lose command of themselves in the troubled waters, 

 so that they are brought helpless to the line on its 

 slope upon which the wave turns ; for it is to be 

 understood that waves do not roll onward in rapid 

 progressive motion as they have the appearance of 

 doing to a spectator, they merely swing in times pro- 

 portionate to their lengths, that is to half the distance 

 between the bottom of the trough and the top of the 

 ridge, as measured on the slope ; and as the turning 

 point, or rather line, taken in the length of the wave, 

 is the place of no upward or downward motion, it is 

 there where the small fishes and other surface animals 

 are accumulated while the storm lasts ; and it is to 

 profit by those accumulations that the divers are 

 found driving through the waves on such occasions. 



Cuvier makes the divers a family consisting of 

 three genera, the divers properly so called, the grebes, 

 and the guillemots ; but as the word diver is in this 

 country restricted to the genus Colymbus, and as the 



