122 



After the parasite has left it the boll worm usually lives for several 

 days, but does not feed at all during that time. Before death it grad- 

 ually shrinks and dries up. Larvae which are parasitized almost always 

 acquire a pale yellowish color and shriveled appearance, which is quite 

 characteristic, even before any other external sign of the parasite is 

 evident. 



Some of the specimens bred out in the laboratory were confined 

 over night with several bollworms in a breeding jar, and from one of 

 these an adult parasite was reared. The life cycle is about three weeks, 

 some nine days of which are spent in the pupal stage. 



At no time have we obtained more than a single specimen of Micro- 

 plitis from one bollworm. 



DESCRIPTION OF MICROPLITIS NIGRIPENNIS ASHMEAD. 



Length, 4 to 5 mm. Black, except the abdomen and legs, which are usually red- 

 dish yellow. Wings very strongly infuscated. Antennae 17-jointed. Head and 



thorax shining black, metathorax 

 coarsely reticulated, with a me- 

 dian carina. Abdominal petiole 

 black at base and remainder of 

 abdomen sometimes much dark- 

 ened. Legs reddish, the coxae 

 more or less black at base. Wings 

 very dark, veins blackish, second 

 cubital cell about as high as long, 

 subtriangular. 



We have bred over fifty 

 specimens of this species, 

 mostly from larvae collected in northern Texas, although the following 

 localities are also represented: Montgomery, Ala.; Tupelo, Miss., and 

 Pine Bluff, Ark. It was bred from larvee collected on the following 

 plants: Cotton, corn, alfalfa, and tobacco. 



The Microplitis is attacked by two species of secondar}^ parasites, 

 but fortunately neither of them has been bred in large numbers. 



The first, Perilampus hyalimis Say, a brilliant metallic blue chalcidid 

 fly (see fig. 24), was bred out on two occasions. The first specimen 

 came from Pine Bluff', Ark., September 13, 1904:, and the second from 

 Ladonia, Tex,, October 14, 1904. The Perilampus issues by gnawing 

 an irregular hole through the end of the Microplitis cocoon. 



The second, 2Iesochorus mnericanus Cress, is a well-known secondary 

 parasite, infesting various species of Braconidse. It was bred on only 

 one occasion, during August, 1904. 



The little chalcidid fly Eii^plectrus comstocki Howard, which usually 

 preys upon the cotton caterpillar, also attacks the bollworm, according 

 to Prof. H. A. Morgan, who has bred the species,^ but we have never 

 met with it in Texas. 



Fig. 24. — Perilampus hyalinus: adult and cocoon (original). 



« Bul. La. Exp. Sta. No. 48, p. 159. 



