*5° 



HA RD WICKE'S SCIENCE- G OSSIP. 



crimson hue. Freshly gathered specimens (May 24, 

 18SS) show albino flowers, mingled with others of 

 pretty pink, in the heads curved before expansion. 

 Some of our wild flowers are of especial interest as 

 being confined to but a single spot in our island, 

 and of these a sad diminution has sometimes taken 

 place owing to accidental circumstances, or the 

 ruthlessness of collectors. It is to be hoped that such 

 may not be the case with this floral gem. 



F. H. Arnold. 



NATURAL HISTORY JOTTINGS. 

 The Green Tortoise Beetle (Cassida viridis), 



{Continued from p. 138.] 



August 2W1.— This evening, which was dull, moist 

 and mild, I took from a thistle three tortoise beetles 

 that had squatted on the centre of the leaf above, near 

 its junction with the stem. From their colour 

 assimilating closely with the colour of the leaf they 

 were not readily distinguishable, their antennae and 

 limbs being tucked away beneath the leaf green 

 carapace which entirely covers and conceals the black 

 head and body ; they were just like so many green 

 scales lying on the leaves. The surface of the leaves 

 was very much blotched by having had the parenchyma 

 eaten out from above in small irregular patches, and 

 the lower epidermis left intact ; and as the tortoise 

 beetle itself eats out the flesh or parenchyma of the 

 leaf (as I have already observed in those evolved 

 within doors), as well as it does its larva, though in a 

 more irregular manner, I am inclined to think that 

 it has been the agent of this state of the leaves on this 

 particular plant. 



As I have taken the imago from the foliage of 

 thistles as early as June 25th, and again on July 20th, 

 and the full-grown larvae (accompanied by younger 

 larvae) not before the second week in August, it 

 would appear that the tortoise beetle hybernates in 

 the perfect state ; when we consider that all those 

 larvae of the August brood are fully evolved in the 

 autumn, and that the food-plant (should the agri- 

 culturist allow it to stand and shed its seed) will die 

 down in the winter, and thus furnish no supply of 

 food to hybernating larvae of a later brood. 



In all its stages the tortoise beetle is well supplied 

 by nature and instinct with the means of concealment 

 and defence. In the perfect or imaginal condition, its 

 form, structure, and colour are such that it can apply 

 itself closely to the foliage of its food-plant, and bear 

 a near resemblance to a green scale (itself not readily 

 distinguished) lying thereon. In the larval condition, 

 its colours are dingy; it is over-shadowed by and 

 concealed beneath its coarse black fecal canopy, 

 which causes it to closely resemble the mutings of 

 those insectivorous birds that affect its haunts ; and 

 its low depressed body is completely surrounded by 

 an armament of strong setose lateral spines, which 



will tend to keep insect foes at bay, and with the 

 hard rough fecal covering it will probably cause birds 

 that may once feed upon the armed larva to consider 

 before again swallowing a morsel that contains more 

 hard, prickly, and innutritious husk than juicy, nutri- 

 tious kernel. In the pupal condition, the colours are 

 again dingy and dark ; the thorax and anterior 

 exposed part of the abdomen are still closely sur- 

 rounded by spines, whilst the last four segments of 

 the abdomen are encased in the run-together exuviae 

 of the anterior portion of the larva, and thus more 

 densely than ever surrounded with setose spines ; and 

 the posterior portion of the exuviae, embracing the 

 six hindermost abdominal segments, is thrown up 

 tensely and vertically, and the anal appendages are 

 thrown apart fork-like and horizontally forwards over 

 the dorsum, by the long fine rigid and elastic anal 

 appendages of the pupa, the whole constituting a 

 densely spinous and elevated anal protection and tail 

 to the insect during this its most helpless stage of 

 existence. Moreover, when even lightly touched, the 

 pupa has the power and habit of suddenly throwing 

 itself up vertically in its anterior three-fourths, and of 

 retaining that position at pleasure. This feat is 

 rendered possible by the manner in which the pupa 

 is secured and retained within and by the larval 

 exuvia : the setose spines of larvahood appertaining 

 to the sixth, seventh, and eight abdominal segments, 

 are now, in the pupa, reduced to mere ridges, and a 

 simple short spine backwardly directed, while the 

 anal appendages (the modified spines appertaining to 

 the ninth and last abdominal segment) are reduced to 

 two long, slender elastic spines ; the former, probably, 

 by an outward pressure, aiding in retaining more 

 firmly the hinder portion of the abdomen within its 

 exuvial sheath ; the latter, undoubtedly, being the 

 main instruments in mooring the pupa, and sometimes 

 visible within the tensely elevated exuvial tail bent 

 back bow-like ; whilst the abdominal exuvial disk 

 remains, firmly glued to its seat, and prevents the 

 pupa falling forwards. 



Kirby and Spence, in their " Introduction to 

 Entomology," in speaking of the genus Cassida with 

 respect to the remarkable habit of its larvoe in shelter- 

 ing themselves under a canopy formed of their own 

 feces, have the following remarks : * "In some 

 species the excrement is not so disgusting as you may 

 suppose, being formed into fine branching filaments. 

 This is the case with C. maculata, Linn. In the 

 cognate genus Imatidium, the larvoe also are merdi- 

 gerous ; and that of /. Leayanum, Latr., taken by 

 Major-General Hardwicke in the East Indies, also 

 produces an assemblage of very long filaments, that 

 resemble a dried fucus or a filamentous lichen." 

 Again, J. O. Westwood, in "An Introduction to 

 the Modern Classification of Insects," says : t "The 

 larvoe of some of the exotic species of Cassida (C. 



* Vol. ii., p. 212 ; ed. 6th, 1S43. 

 f Vol. i., p. 379 ; ed. 1839. 



