63 



NATURAL ENEMIES. 



I gave above an account of the Ked-tailed Tachina-fly (Exorista 

 leucaniace, Kirkpatrick,) and of the Military Microgaster (Microgaster 

 militaris, Walsh). These are the only parasites that I have ever 

 bred from the Army-worms. I found three or four larvte of Janus 

 Ground-beetle {Galerita janus, Fabricius) in company with the 

 Army- worms which I found in the Hungarian field, and as these 

 larvae are known to be predaceous I have no doubt that they destroy 

 large numbers of the Army-worms. These larvae quite closely re- 

 semble that of Galerita lecontei* Dejean, but differs by having the 

 femora or thighs of the first pair of legs but slightly larger than the 

 others. Its body is nearly cylindrical ; the first segment is the long- 

 est, and tapers toward the head. The head is widest in front, from 

 whence it tapers posteriorly, but is wider at its junction with the 

 first segment than the latter is ; it is of a yellowish-brown color, 

 and from the middle of the face arises a cylindrical yellowish pro- 

 tuberance, which terminates in two short prongs. The body is of a 

 black color, and the sutures of the segments are a dull greasy-white. 

 The venter is also of this latter color, and is marked with five rows 

 of black spots, those in the middle row the largest. On the poste- 

 rior end of the last segment are two divergent bristles, which are 

 about three-fourths as long as the body, including the head ; they 

 are of a black color, with their bases yellowish. When fully grown, 

 this larva measures about three-fourths of an inch in length. 



The pupa closely resembles that of Galerita lecontei,^ Dejean. It 

 is of an elongate elliptical shape, rounded behind, of a yellowish- 

 white color, and is thinly covered on the back of the abdomen with 

 short reddish hairs, which grow mostly in clusters or small patches. 

 The eyes are dark- brownish. Two of the leg-cases project about one- 

 eighth of an inch beyond the tip of the abdomen, and are united 

 nearly to their tips, each of which is divided into two prongs. On 

 each side of each of the abdominal segments one, three, four, five 

 and six, is a long, cylindrical, whitish projection, thickened at its 

 base, and having at its outer end a small bulb which bears one or 

 two stiff, reddish bristles. This pupa measures, from the fore part 

 of its head to the tip of its abdomen, less than one-half of an inch. 



The perfect beetle has a black head, blue-black wing-cases and 

 yellowish- brown legs and thorax, and measures nearly three-fourths 

 of an inch in length. 



On the 21st of August I found a larva of this species running 

 over a bare piece of ground. I placed it in one of my breeding 

 cages, and shortly afterward threw a Cabbage-worm {Pieris rapce, 

 Linn.) into its cage. This it quickly seized in its jaws and soon 

 extracted its juices. On the 23th of August this larva became a 

 pupa, and the perfect beetle issued on the loth of the following 

 September. 



I have pretty good evidence that the common Striped Gopher 

 occasionally feeds upon Army-worms. Several years ago I shot one 

 of these animals as it was running towards its burrow in a timothy 



*Figured on page 433 of "Packard's Guide to the Study of Insects" (Fig. 370), and repro- 

 duced on page 153 of the "American Entomologist, Vol. III. (Fig. 57). 

 + Figured in "Packard's Guide to the Study of Insects," page 433, Fig. 371. 



