Some Illinois Microgasters. 5 



larvae. Hence these insects should be known as A. congregates, 

 Say, var. orohence, Forbes. 



Apanteles militaris, Walsh. 



This well-known species, as would be expected from a 

 knowledge of its habits, was found in especial abundance dur- 

 ing the years when the army worm was destructive. In 1882 

 specimens were sent to the office by Mr. D. S. Harris, of Cuba, 

 HI., with the statement that he had bred them from the army 

 worm, which was then very abundant in that vicinity. Bur- 

 ring the same season, this notorious pest was destructively 

 abundant in certain portions of McLean Count}'^, but its opera- 

 tions were rapidly checked by A. militaris^ which is the species 

 referred to by Prof. Forbes on page 102 of his First Report (the 

 twelfth of the series). Describing the history of a brood of 

 worms observed in a certain field, he writes: "When first no- 

 ticed, on the 24th of June, these worms were doing serious 

 damage to a heavy growth of timothy on high ground, march- 

 ing from one side of the lawn to the other. B}^ the 3d of July, 

 the season for the transformation to pupee had been reached, 

 but apparently not over twenty-five per cent, of the worms suc- 

 ceeded in effecting the change, the remainder dying in such 

 numbers that the ground was reeking with a sickening stench. 

 At the same time clusters of the cocoons of one of the common 

 parasites of the army worm were found everywhere abundant 

 on the surface of the ground, and in some cases on the dried 

 remains of the army worm itself. Of seventy-six pupte of the 

 worm, collected in this field at this time, but one reached 

 maturity." From cocoons collected in this field July 2, the 

 adult Apanteles continued to emerge until July 20. 



The only specimens bred in 1886 were from a mass of 

 thirty-nine white cocoons loosely fastened togther, parallel to 

 each other, found on a leaf of Indian corn in the field, August 

 2. The flies emerged August 11. 



Apanteles cacceci^, Riley. 



A single specimen (?) of this species was bred during May, 

 1886, from a larva of Teras minuta^ Robinson (nialivorana, 

 Le B.; Cinderella, Riley). The cocoon was attached to a leaf. 

 It is thin and white, 6 mm. long and about one third as wide. 



