THE YOUNG NATURALIST. 



891 



Fluviatllis. — This shell is oval and 

 oblique, with a very small spire, and rather 

 large half-moon shaped aperture, the shell is 

 solid and whitish, marked all over the outer 

 surface with a sort of net-work pattern in 

 purplish red, or blue-black, thes ? marl ings 

 being very variable both in coloring and 

 design. The operculum is shelly, with a small 

 spire, and a hooked process which fits under 

 the columella, and acts like a hinge. They 

 may be found in rivers and running streams, 

 adhering to stones, chiefly in the eastern and 

 south-western countries. The empty shells 

 are often gathered on the sea beach. 



(To be continued .) 



DIFFICULTIES FOR 

 BEGINNERS. 



NO. i. — CARADRINA ALSINES. AXD 

 BLANDA. 



There are several species of Lepidoptera 

 so very like another species that it is some- 

 times impossible, and often very difficult even 



between the stigma and the base of the wing, 

 In most of specimens there is also a darker 

 shade in the lower half of the wing from the 

 bottom of the renifcrm stigma. These marks 

 however are all indistinct and vary more or 

 less in different specimens. To separate the 

 two you will do best with a long row of them, 

 then pick out the darker specimens. If they 

 are an Jine condition, you will find some of 

 them have a faint violet tinge; These are 

 Blanda, and if you can pick out one or two by 

 this characteristic you will not find it so 

 difficult to separate the others. Blanda is 

 darker than Alsines and though the mark- 

 ings are exactly the same, in both species 

 they are not so distinctly noticeable in Blanda. 

 In Alsines the stigma, lines, and the shade 

 between the stigma, are distinctly darker than 

 the ground color. In Blanda while the 

 stigma are visible enough from the yellowish 

 margin, the color is scarcely darker than the 

 rest of the wing. When you have separated 

 them by their color, and the difference in the 

 distinctness of their markings you will- soon 

 for an experienced collector to separate them. | satisfy yourself if you have got them right, 

 What is difficult for an experienced collector, | but be ver >" careful to compare specimen that 



is much more so for a beginner, and as the 

 season for studying and arranging our \ jar's 

 captures is now at hand, we propose to give 

 an occasional article, on some of these 

 difficult species that may help our readers by 

 pointing out some of the known differences 

 in the color, markings, &c. The first to 

 which we shall direct attention are the psir 

 whose names stand at the head of this article, 

 Garadrina Alsines and Blanda. They are two 

 dull colored, indistinctly marked insects, 

 without any very striking characteristic. 

 Very few, we believe, are able to discriminate 

 between them with any certainty, and he 

 certainly is a good judge who could name 

 either at night, without comparison with the 

 other. They are dull brown in color, the 

 discoidal marks (stigma) are rather darker 

 than the ground color, and edged with paler, 

 Between it and the stigma is another line, : 

 generally broken up into dots, and another 



are equal in condition. Bred specimens of 

 one must be compared with bred specimens 

 of the other, fine specimens with fine 

 specimens, or you will still get astray. As to 

 poor specimens, we would advise you not to 

 admit them, for you will never have any 

 satisfaction with them. 



The young larva have not yet been separated 

 by any recognizable mark : when full-fed they 

 are not so difficult. A full description of both, 

 by the Rev. Harper Crew, is published in the 

 Zoologist for August, i86i,and quoted iniVf^'- 

 man's Moths, fcb which we refer our readers. 

 The distinctions may be briefly summed up. 

 Alsines is reddish-drab, the back tinged with 

 purplish brown, the dorsal line whitish bordered 

 at centre of each segment with black. Blanda is 

 yelloish-drab, the back slightly marbled with 

 black ; the dorsal line is yellowish, edged with 

 ^black between the segments, but entirely black 

 at the centre of each of them. 



