70 



ViG. 35. 



The larger species of Bracon are usually black, with bright red abdomen, 



dark, smoky wings, and a long ovipositor. They 

 may be seen upon dead trees, and are largely para- 

 sitic upon the larvae of beetles which infest the 

 trees. The larva of the Bracon spins a tough oval 

 cocoon, perfectly flat above and below. Such 

 cocoons can frequently be found under the bark of 

 maple, cedar, etc., in the burrows of the beetles 

 upon which the parasites preyed. The smaller 

 species are reddish or yellowish, and infest 

 dipterous and other larvae. Fig. 35 shows Bracon 

 charus which is said to be a parasite of Chrysoho- 

 thris femorata, the flat-headed apple tree-borer. 



The species of Bhogas diflfer from Bracon in 

 having the ovipositor short, the wings transparent, 

 and especially in having the first segments of the 

 abdomen carinate. R. intermedius is a medium 

 sized yellow species which I have frequently bred 

 from a handsome caterpillar (Acronycta sp.) 



Many larvae live in one caterpillar, which dies from the attack when it is about 

 full grown. The victims may frequently be seen extended on stems of grass, appar- 

 ently at rest, but on closer examination are found to be stiff" and hard, and per- 

 haps riddled with minute holes from which a score or more of the flies have 

 issued. 



Cryptogastres. — The species included in this division are easily recognized 

 by the form of the abdomen which, instead of consisting of several segments, 

 with sutures (or joints) between them, seems to be in one piece. This shield-like 

 abdomen, however, consists of the first three segments welded together. It con- 

 ceals the ventral segments, and thus gives the name to the division, which con- 

 tains the two sub-families, Sigalphinae and Cheloninae. 



Fig. 36 shows very clearly the male and female of Sigalphus curculionis, 

 which is one of the parasites of the 

 plum-curculio. 



Areolarii. — In this division 

 the distinguishing feature is in the 

 venation of the wing, in which the 

 second submarginal is minute, form- 

 ing a small triangular areolet, or often 

 imperfect. There are two subfamilies 

 as in the preceding division. The 

 first includes the well-known genera 

 Apanteles and Microgaster ; each con- 

 taining many species, which, though 

 small, are of great benefit in holding 

 lepidopterous larvae in check. Mr. Howard (in Scudder s Butterflies of the United 

 States and Canada) mentions no less than sixteen species of Apanteles as para- 

 sites of butterflies, 



PoLYMORPHi. — This division contains several subfamilies, and includes some 

 large species, such as Helcon, but it is almost impossible without illustrations to 

 give any satisfactory idea of the numerous genera. Fig. 37 shows, greatly enlarged, 

 MacTocentrus delicatus, a parasite of the Codling moth. 



IiG. 36. 



