48 AMERICAN ENTOMOLOGY. 



adipose part of the system, and spare the vitals until the former 

 is exhausted. By this selection, the life of the larva is continued 

 until the parasite obtains its full size, and is prepared to enter 

 into the state of pupa. The larva then attaches itself firmly to a 

 fixed surface by means of its feet, and dies. The pupae, secure 

 within, await their destined period in tranquillity, and the in- 

 cluded insects finally emerge from their contracted boundaries, 

 by gnawing a passage through their own indurated covering, as 

 well as through the common integument of the larva. 



Ichneumon devinctor. — Specific character. Black ; abdo- 

 men rufous ; scutel, annulus of the antennse and of the tibiae, 

 white. 



Desc. Body black : antennae rather short, annulus pure white, 

 commencing at the ninth joint, and extending to the eighteenth : 

 scutel pure white : wings dusky violaceous : abdomen, with the 

 exception of the first segment, bright rufous : tibiae, excepting at 

 base and at tip, pure white : anterior and intermediate tarsi, with 

 the first joint, white at base. 



Ohs. This species is not very common. I obtained a specimen 

 in the North- West Territory. An individual occurred in Mis- 

 souri, that may, perhaps, be only a variety of the present species ; 

 it is smaller, and has ferruginous, instead of white, on the feet. 



The upper right figure. 



Ichneumon unifasciatorius. — Specific character. Black ; 

 annulus of the antennae, two scutellar spots, and band near the 

 base of the abdomen, white. 



Desc. Body black : front, nasus, and line on the frontal and 

 exterior orbits, white : antennae moderate, with a white annulus 

 beginning at the fifteenth joint, and extending to the twenty-first 

 joint : thorax with two abbreviated white lines on the middle ; 

 an oblique line each side before the wings, wing scale, and 

 small spot beneath the wings, white : scutel white, with a small 

 transverse white spot at its tip : wings fuliginous : abdomen de- 

 pressed, rather slender ; first segment white at tip, forming a 

 band : tibiae white on the exterior side. 



Ohs. This insect is of frequent occurrence in all the Middle 

 States. There is a variety, of which the abdomen is very slightly 

 tinged with rufous. Allied to nigratorms Fabr., but may be dis- 

 tinguished by the band on the first segment of the abdomen, and 



