55 



TORTOISE BEETLES. 



BY F. B. CAULFIELD, MONTREAL. 



The tortoise beetles as they are called, from their resemblance in shape to a 

 turtle or tortoise, belong to the great family of leaf-eating coleoptera, the Chry- 

 somelidcB, but were formerly classed as a distinct family, the Cassidadce, a term 

 signifying a helmet, the fore part of the thorax generally projecting over the 

 head like the front of a helmet. In the members of this family the body is 

 generally of a broad, oval form, flattened beneath, convex above. The antennae 

 are short and thickened at the tip, presenting somewhat the appearance of a club. 

 The head is small and generally hidden beneath the overlapping edge of the 

 thorax, and the legs are very short, not extending much beyond the margin of 

 the wing covers, so that the resemblance to a tortoise is really striking. The 

 larvae of many kinds of insects are protected from the burning sunshine and the 

 attacks of their enemies by a coat of hair or prickly spines, or else conceal them- 

 selves beneath leaves or in crevices during the hotter parts of the day, but the 

 insects in question adopt an entirely different plan, and shelter themselves beneath 

 umbrellas, covered, not with silk or cotton, but with a mass of their own excre- 

 ment. 



In most of these creatures the body resembles the perfect insect in shape, 

 being broad and flattened, but they diflfer in having a row of spines on each side 

 and in being provided with a tail, and a very remarkable tail at that. This 

 instrument resembles in form a fork, with a rather thick, rounded handle, from 

 which project two long prongs. This forked tail is curved over the creature's 

 back, and upon the prongs and lateral spines the excrement is heaped until a mass 

 almost as large as the creature's body is accumulated. Our Canadian species of 

 tortoise beetles belong to three genera — Physonota, Goptocycla and G/ielymorpha. 

 Physonota helicLnthi, Eand, lives on the wild sunflower (Relianthus), and soon 

 after these have leafed out in spring, such of the beetles as have survived the 

 winter gather upon them. They are now of a bright, golden-green colour, and are 

 exceedingly beautiful, gleaming and flashing like gsms in the sunshine. Soon 

 after this the eggs are deposited in an irregular cluster, covered with a gummy 

 exudation which hardens on exposure bo the air. This cluster is placed on the 

 upper surface of the leaf, and near the tip just where it tapers to a point. 



The larvae are oblong-oval in shape, and when full grown measure nearly an 

 inch in length. The general colour is dark olive green, and on the back are three 

 shert yellow stripes, that in the centre being a little the longest. On each side 

 is a row of ten simple spines. When undisturbed these slug-like larvae keep the 

 tail curved over the back, and both body and tail are constantly wet with semi- 

 fluid excreta, so that the form of the creature can hardly be seen. From the 

 middle of July to the end of August these larvae change to chrysalids, and by the 

 end of the latter month and during September the beetles emerge, and may be 

 found resting quietly on the leaves of their food plant. They are now dressed in 

 a coat of sober black, irregularly spotted with creamy white, very pretty little 

 fellows in a neat evening dress, but very different to the magnificent marriage 

 garment worn by their parents amidst the fresh green leaves and glowing sunshine 

 of the early summer. 



The beetles appear to eat very little, but the larvae are hungry creatures, 

 eating numerous holes in the leaves, and when abundant almost stripping the 

 plants. 



