NEW YORK STATE MUSEUM 



The Braconidac include some very important parasites, specially of 

 wood-borinL,^ larvae and of a numljcr of leaf feeders. This group may be 

 best recognized by such species as B r a c o n simplex Cress., a form which 

 is well known to live on a number of borers, and also by the tiny Micro- 

 gasters, minute species which frccpicntly occur in immense numbers in our 

 larger leaf feeders, and when maturity is attained, make their way out 

 through the body wall of their hosts and spin tiny, nearly cylindric, snow 

 white cocoons on the Ixuly of the victim, as represented at plate 44, figure 2. 



The Evaniidae or ensign Hies, as they are termed by Professor Corn- 

 stock, constitute a parasitic group wdiich may be easily recognized by the 

 peculiar manner in which the abdomen is carried. The latter is quite 

 slender, attached to the dorsum of the metathora.x, and is carried in an 

 elevated position resembling a flag or ensign. 



The Chalcididae comprise an immense number of very small parasites, 

 some of which are exceedingly valuable agents in controlling our native 

 insects. A number of species are noticed in connection with their hosts and 

 the general characteristics of the group may be learned by reference to 

 sui)sequent pages. 



The Proctotrypidae in s|)ite of the long family name, arc smaller insects 

 than the preceding and a numlicr of them are well known as important egg 

 parasites of some of our more injurious species. 



Practically all of the dipterous parasites belong to the Tachinitlae, a 

 large- family which com])rises forms having much tlu' a[)pcaranct: of the 

 common hovise tly. These insects are more general in their food habits 

 than most of the hymenopterous jjarasites and fre(]uently attack insects 

 l)elonging to \ery different groups. ()ccasionall\- niem!)ers of this family 

 are exceedingly abundant and have a very important part in reducing the 

 numbers of some insect pest. This is particularly true of the notorious 

 army worm, HeIio])liila tini])uncta llaw. It has been recorded in 

 connection with this latter insect that its parasites are sometimes so abundant 

 as to appear in swarms about their victims and it is by no means uncommon 

 to meet with an army worm bearing from 6 to 7 or even more pearly white 



