Some species pupate in silken cocoons on the outside of the body of the host.

STEPHANIDS Family Stephanidae Not illus.

Identification: Costal cell present. Head spherical on long neck and bearing a crown of teeth. 5-19 mm. Gasteruptiids and aulacids (p. 334) are similar but do not have a crown of teeth, and abdomen is attached to propodeum high above hind coxae.

This is a small group of very rare insects. Larvae are parasites of wood-boring beetles.

ICHNEUMONS Family Ichneumonidae See also PI. 15

Identification: Slender, wasplike, 3-40 mm. 2 recurrent veins. 2nd submarginal cell small or lacking. Base of cubital vein lacking, 1st submarginal and 1st discoidal cells fused. Antennae with 16 or more segments and usually at least half as long as body. Braconids have only 1 recurrent vein or none; gasteruptiids and aulacids (p. 334) have head set out on a slender neck, the abdomen attached high above hind coxae, and FW with a costal cell; wasps (Scolioidea, Vespoidea, and Sphecoidea, pp. 340, 346, 348) are usually stouter-bodied, with shorter antennae (that nearly always have 13 or fewer segments), 1 trochanter segment, a costal cell, and the cubital vein complete; trigonalids (p. 340), which have long many-segmented antennae, have a costal cell and a complete cubital vein.

This is the largest family of insects, with over 3000 N. American species. They are common insects, found almost everywhere. They vary greatly in size and color: many are uniformly colored, from yellowish to black, and many are brightly patterned with black and brown or black and yellow; many have middle segments of antennae yellowish or whitish. Most species have a long ovipositor.

Most ichneumons do not sting, though they generally try to do so when handled. The few that will sting are usually large, yellowish brown, and have a laterally flattened abdomen. These ichneumons have a short, sharp ovipositor capable of piercing the skin. They must be able to move the abdomen in order to sting, and if grasped by the abdomen are quite harmless.

The family Ichneumonidae is divided into a number of subfamilies, many of which are further divided into tribes. Each subfamily or tribe is often parasitic on a particular group of insects. Many ichneumons are of value in the control of noxious insects.

Chalcids: Superfamily Chalcidoidea

Pronotum in profile somewhat squarish and not quite reaching tegulae. Antennae elbowed and usually short, with 5-13 segments. At least 1 pair of trochanters 2-segmented. Ovipositor generally short, occasionally as long as body, and usually rising in front of apex of abdomen. Wing venation greatly reduced. Mostly 5 mm. or less. Small Proctotrupoidea (p. 335) with elbowed antennae and a similarly reduced venation have the pronotum more triangular and the ovipositor apical.

This is a large group occurring almost everywhere. Most chalcids are black, blue-black, or greenish, and many are metallic. Wings are usually held flat over abdomen at rest; a few are wingless or have wings greatly reduced. Most larvae are parasites of other insects and some are hyperparasites; many are plant feeders.

The small size of most chalcids is likely to make their identification difficult; the key below is designed to aid the beginner in separating the families of chalcids.

1. HW very narrow, almost linear Mymaridae (p. 324)

1'. HW elongate-oval, not linear 2

2(1'). Tarsi 3-segmented Trichogrammatidae (p. 324)

3(2'). Tarsi 4-segmented; apical spur of front tibiae small and straight Eulophidae (p. 324)

3'. Tarsi 5-segmented; apical spur of front tibiae large and curved 4

4(3'). Head of 9 oblong, with a deep longitudinal groove above;

cf wingless; front and hind legs stout, middle legs slender Agaonidae (p. 328)

4'. Without this combination of characters 5

5(4'). Mesopleura convex; apical spur of middle tibiae large and stout Tanaostigmatidae, Thysanidae,

Eupelmidae, Encyrtidae, Eutrichosomatidae (p. 326) 5'. Mesopleura with a broad shallow groove; apical spur of middle tibiae small 6

6(5'). Mandibles sickle-shaped; thorax strongly arched, the pronotum usually not visible from above; scutellum large; abdomen laterally flattened Eucharitidae (p. 326) 6'. Without this combination of characters 7

7(6'). Hind femora greatly enlarged and usually toothed beneath Chalcedectidae, some Torymidae,

Leucospididae, Chalcididae (p. 328) 7'. Hind femora slender, not greatly enlarged 8

8(7'). Hind coxae considerably larger than front coxae

Torymidae, Ormyridae (p. 328) 8'. Hind coxae little if any larger than front coxae

Pteromalidae, Perilampidae, Eurytomidae (p. 330)

FAIRYFLIES Family Mymaridae

Identification: HW very narrow, almost linear.

Fairyflies are minute insects, mostly less than 1 mm. (smallest is only 0.21 mm.), usually blackish, with relatively long legs and antennae. Larvae are egg parasites.

TRICHO GRAMMATID S Family Trichogrammatidae

Identification: Minute insects, 1 mm. or less, and rather stocky in build. Tarsi 3-segmented. Tiny hairs of wings usually in rows.

Larvae are parasites of insect eggs, and some are of value in controlling insect pests.

EULOPHIDS Family Eulophidae

Identification: 1-3 mm. and varying in shape and color; most are black, a few brilliantly metallic. Tarsi 4-segmented. Apical spur of front tibiae small, straight. Axillae extend forward beyond tegulae. cf antennae often pectinate.

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