52 



SECOND ANNUAL REPORT OF 



[Fig. 19.] 



antennse, and one stiffer and longer bristle at top of cheeks ; front, dusky, ferruginous, with two 

 rows of black converging bristles; divided by a broad depressed stripe of a brighter ferruginous 

 color and without bristles ; occiput bright ferruginous ; labium ferruginous with hairs of same 

 color; maxipalps rufous ; eyes dark mahogony-brown, and perfectly smooth; antenna?, two basal 

 joints rufous, with black hairs, third joint flattened, dusky,, and thrice as long as second; seta, 

 black ; entire hinder part of head covered with dense white hairs. Thorax, more decidedly blue 

 than in leucanice, broader (instead of narrower) in front than behind ; the vitta? less distinct ; scute* 

 of same color as thorax. Abdomen, stout and more cylindrical than in leucanice; first joint dark 

 bluish-gray ; second, light bluish-gray, becoming darker along the middle, at sides and at lower 

 border ; third joint, like second above, but golden-gray at sides (no rufous); last joint entirely yellow 

 or pale orange, with no other color and but few black bristles around anus. Wings more dusky 

 than in leucanice; alula?, opaque bluish-white. Legs, black ; pulvilli pale yellow. 



Described from one captured, 4 bred § . Space between eyes at occiput fully one-third the width 

 of head. 



To give an idea of the other parasites which attack the 

 Army-worm, I will briefly allude to them, and transmit 

 descriptions for the scientific reader. 



The Glassy Mesochorus — Mesochorus vitreus, Walsh. (Fig. 19.) — Length of 

 body .08 inch, (two millimetres,) to .13 inch, (three millimetres) ; the small speci- 

 mens being parasitic on the Army-worm and the large ones captured in Rock Is- 

 land county. Male, general color light rufous. Eyes and ocelli, black ; antenna; 

 fuscous, except toward the base. Upper surface of thorax in the larger specimen fuscous ; inter, 

 mediate and posterior tibia? with spurs equal to one-fourth of their length ; posterior knees slightly 

 dusky ; tips of posterior tibia; distinctly dusky. Wings hyaline ; nervures and stigma, dusky. 

 Abdomen, a translucent yellowish-white in its central one-third; the remaining two-thirds piceous- 

 black, with a distinct narrow yellowish annulus at the base of the third joint. In the larger speci- 

 men, which seems to be immature, the basal abdominal joint, and the articulations of the terminal 

 joints are light rufous. Appendiculum of the abdomen composed of two extremely fine seta?, thick- 

 ened at their base, whose length slightly exceeds the extreme width of the abdomen. 



The female differs from the male, in the head from the mouth upwards being piceous. The 

 thorax and pectus, in all three specimens, are also piceous-black. Abdomen as in the smaller 

 male. Ovipositor, which is dusky, slightly exceeds in length the width of the abdomen. 



The Diminished Pezomachiis — Pesomachus minimus, Walsh, (Fig. 20.). — Length of the body 



[Fig. 20.] 



.07 to .10 inch., (2 to 2£ millimetres). Male, general color, [Fig. 21.] 

 piceous. Eyes black; antenna? black, except toward the 

 b:ise, where they are light rufous. Legs rufous ; hind legs a 

 little dusky. Abdomen narrowed; second and sometimes ^'jSju: 

 | the third joint annulate with rufous at tip. The female dif-|g i-llftlll^ 1 jy 

 fers from the male in the thorax being almost invariably L^j-J &f 

 rufous, and in the first three abdominal joints being gener- 

 ally entirely rufous, with a piceous annulus at the base of the third, which is sometimes absent. 

 The abdomen is also fuller and wider. Ovipositor dusky, equal in length to the width of the 

 abdomen. No vestige of wings in either sex, and the thorax contracted and divided as in Formica. 



Fig. 22.] The larvae of this species issue from the body of the 



Army- worm, and spin on its skin, small cocoons symmetric- 

 ally arranged side by side, and enveloped in floss (Fig. 21). 

 It belongs to a genus of wingless Ichneumons, and in its turn 

 is preyed upon by a small Chalcis fly (Chalcis alhifrons, 

 Walsh) which is represented at Figure 22. 



The Military Microgaster— Microgaster militaris, Walsh, (Fig. 23). — Length 0.07 inch. 

 [Fig. 23.] Head black; palpi whitish ; antenna? fuscous above, light brown beneath towards 

 the base. Thorax black, polished, with very minute punctures. Wings hyaline ; 

 nervures and stigma fuscous ; lower nervure of marginal, and exterior nervure of 

 second submarginal cellule entirely obsolete. Lower nervuleof third and terminal 

 'submarginal cellule, hyaline. Legs light rufous, posterior pair, with knees and 

 tips of tibia? fuscous. Abdomen black, glabrous, highly polished. Ovipositor not 

 exserted. 



The cocoons of this little parasite are spun in irregu- 



