236 



TRANS. ST. LOUIS ACAD. SCIENCE. 



The insects which meet their death in this pitcher comprise 

 numerous species, and are of all orders ; but, as one might natu- 

 rally infer, the ubiquitous, honey-loving ant is the principal vic- 

 tim. But, while most insects fall an easy prey to the mechanical 

 and secretory allurements of the plant, there are two species more 

 especially which are proof against those allurements, and which 

 seem to be invariable accompaniments of the tube-like leaf — 

 the one feeding upon it directly, the other sponging upon the 

 captured and macerated insect-remains. Of these two insects, I 

 herewith submit full descriptions. 



{Fig-. 10.] 



The first is Xanthoptera semicro- 

 cea Guen., kindly determined by Mr. 

 A. R. Grote of Buffalo, N. Y., our 

 leading authority on the Noctuidae. 

 It was many years ago figured, in 

 a yet unpublished plate, by that 

 ardent entomologist, John Abbot, 

 who, toward the close of the last 

 century, did so much to clear up the 

 natural history of North American 

 moths. Guenee's descriptions were 

 made from these drawings, and, as a 

 consequence, are not as complete as 



one could wish. I am not aware that the insect has ever been 

 definitely referred to by any other authors, and its complete natu- 

 ral history has certainly remained unknown. The egg is laid 

 within the tube, and the young larva covers the smooth surface 

 with a fine gossamer-like web, generally closing up the mouth by 

 webbing the lips together. As it increases in size it frets the leaf 

 within, feeding on the parenchyma and leaving only the epider- 

 mis. Its ochre-colored excrement falls in pellets to the bottom 

 of the tube, where it gathers in a compact mass above the putrid 

 remains of the insects which had been captured before the closing 

 of the mouth. The transformations are undergone in a slight 

 cocoon usually constructed just above the mass of excrement. 

 There are at least two broods of the insect each year, the first 

 larvae appearing during the early part of May, the second toward 

 the end of June. 



Xanthoptera semicrocea. — a, 

 egg, enlarged, the natural size indi- 

 cated at side; h, c, larva, back and 

 side views; rf, chrysalis; «, moth, nor- 

 mal form, with wings expanded;/", 

 pale variety, with wings closed; ff, 

 enlarged tubercle of larva. 



