026 AN INTRODUCTION TO ENTOMOLOGY 



found in the present subfamily only in this tribe and in the Pimplini. 

 Caterpillars boring in twigs or weeds are the usual hosts of those with 

 long ovipositors. The rest attack cutworms and similar caterpillars. 

 Gljpta rufiscutelldris is a common parasite of the oriental fruit moth. 

 In some localities it gives a moderately effective control of this pest. 

 The genus Ceratogdstra contains wasp-like species with conical 

 pointed abdomens. They are commonly found on goldenrod flowers. 



Subfamily TRYPHONIN^ 



The Tryphoninse includes most of the ichneumon flies that attack 

 sawfiies, and the group is most abundant in our northern forests. In 

 the tropics, where sawfiies are scarce, few species occur. Some Try- 

 phoninas are slender, pale brown in color, and have large eyes. 

 They fly at night and are often confused with the superficially similar 

 Ophioninas but may be at once distinguished from these by their 

 possession of an areolet and by the characters given in the key to 

 subfamilies. 



The tribe Tryphonini contains short stocky species with the 

 propodeum divided into many areas by cross and longitudinal 

 carinse. Most of the species are black with the abdomen and legs 

 largely reddish. The life history is quite characteristic of this and 

 related groups. The egg is large and oval with a slender stalk. The 

 female inserts the stalk of the egg into the skin of a sawfly larva 

 near its head where the larva cannot turn to reach it with its mandi- 

 bles. The stalk stays embedded in the larva's skin, anchoring the 

 egg in place. After the sawily spins its cocoon the egg hatches into 

 a small larva which feeds on the host until it is consumed. The 

 parasite pupates to emerge as an adult the following spring to para- 

 sitize the next generation of sawfiies. A female may often be seen 

 with an egg ready for deposition attached by its stalk to her ovipositor, 

 and in the genus Polyhldstus a dozen or more eggs may be carried on 

 the ovipositor at once. The older eggs, those near the tip of the 

 ovipositor, contain fully developed larvae. It is said that if a host is 

 not found soon enough the oldest eggs are discarded. 



The tribes Mesoleiini and Mesoleptideini contain species usually 

 more slender than the Tryphonini and with the propodeum not 

 divided into numerous areas by carinae. These tribes also parasitize 

 sawfiies, but the egg does not have a stalk and is inserted into the host 

 larva. 



The tribe Metopiini contains species that are usually black, with 

 a very protuberant face, and short stout legs. Most of the species 

 are small, though the genus Met dp his contains fairly large individuals. 

 The Metopiini are parasites in lepidopterous pupse. The genus 

 Metacaliis contains two cosmopolitan parasites of clothes moths. 



The tribe Diplazonini contains small stocky bright-colored species 

 with the upper tooth of the mandible broad and chisel-shaped. All 

 are internal parasites of aphid-eating syrphid larvae. The adult 

 emerges from the host puparium. Dipldzon IcEtatdrius is a species 

 that is common all over the world. It may be recognized by its 

 black-, white-, and red-banded hind tibia, 



