60 SECOND ANNUAL REPORT OP 



of the fork. They are especially recognizable in the Mottled Tortoise 

 beetle {Cassida guttata* Oliv., Fig. 36,) mentioned below, which re- 

 moves most of its dung before each moult. 



Fi s- 31 - The eggs from which these larvae hatch, are de- 



posited singly upon the leaves, to which they are fas- 

 tened by some adhesive substance. They are of 

 irregular angular form; flat, and somewhat narrower 

 at one end than the other; ridged above and at the 

 sides, but smooth and obovate below. They are usually 

 furnished with spine-like appendages, which however 

 are sometimes entirely lacking. They look, in fact, 

 very much like miniature specimens of those curious 

 skate-barrows or Mermaid's purses, which are found 

 so commonly along the sea-shore, and which are the 

 empty egg-shells of certain kinds of Ray-fish or Skate. Those of the 

 common Golden Tortoise-beetle (Fig. 31,) are 0.04 inch long, and of a 

 dull, dirty white color. 



The Tortoise-beetle larvee, when full grown, fasten the last two or 

 three joints of the body to the underside of a leaf, by means of a 

 sticky secretion, and in about two days change to pupae. The pupa 

 of those species which have 32 barbed spines, is flat with usually 

 four or five broad but thin and transparent serrated leaf like appen- 

 dages on each side of the abdomen, and the prothorax, which is greatly 

 dilated and covers the head, is furnished around the edge with smaller 

 barbed spines. The broad leaf-like spines at the edges of the body 

 are bent under while the transformation is being effected, but are 

 soon afterwards stretched stiffly out with a forward slant. The pupa 

 loses the pronged tail, but as the old larval skin is left adhering to 

 the terminal segments the prong of dung still protects it in most 

 cases. The legs and antenna? are not free in this, as in the pupas of 

 most other beetles, but are soldered together as in the chrysalis of a 

 butterfly, and yet it has the power of raising itself up perpendicularly 

 upon the tail end by which it is fastened. The pupa state lasts about 

 a week. 



Having thus spoken in general terms of this anomalous group of 

 beetles, I shall now refer more particularly to a few of the species. 

 Most of those mentioned below infest the Sweet-Potato both in the 

 larva and perfect beetle states. They gnaw irregular holes and when 

 sufficiently numerous entirely riddle the leaves. They usually dwell 

 on the underside of the leaves, and are found most abundant during 

 the months of May and June. There must be several broods during 

 the year, and the same species is often found in all stages, and of all 

 sizes at one and the same time. In all probability they hybernate in 

 the beetle state. 



I have proved by experiment that Paris green — one part of the 

 green to two of flour — when sprinkled under the vines, will kill these 

 insects, though not near so readily as it does the Colorado Potato 



