Parasitic Hymenoptera Ants Wasps and Bees Suborder Apocrita

Base of abdomen constricted, sometimes distinctly stalked. Thorax contains a 4th segment, the propodeum (actually the basal abdominal segment, fused to thorax). Wings without an accessory vein and HW with not more than 2 basal cells; venation in some minute forms greatly reduced, almost lacking.

Many Apocrita larvae live as parasites in or on bodies of other insects or spiders, and many are plant feeders. Parasitic forms generally lay their eggs on, in, or near body of the host; many have a long ovipositor with which they reach hosts in cocoons or other seemingly protected situations; a few lay their eggs on vegetation, and the newly hatched larvae remain on the vegetation until they can attach to a host passing by. From 1 to many parasites may develop in a single host individual (depending on species of parasite); the host is nearly always killed by the parasite, but usually not until the parasite has completed its larval development. Many parasitic Apocrita are very valuable insects, since they aid in the control of noxious species.

This suborder is divided into 11 superfamilies, adults of which can usually be separated by the character of the pronotum, antennae, and ovipositor, the number of trochanter segments, and the wing venation. Pronotum in profile may appear (a) more or less triangular and extending nearly to the tegulae (small scalelike structures overlying bases of front wings), (b) more or less squarish and not extending to the tegulae, or (c) short and collarlike, with a small rounded lobe on each side that does not reach the tegulae. Antennae vary in number of segments they contain and in whether or not they are elbowed; the 1st segment of an elbowed antenna is much longer than any other segment, and in nonelbowed antennae is comparatively short. The distinction between "elbowed" and "not elbowed" is occasionally not very sharp. The terminal antennal segments are usually slender, but are sometimes swollen to form a club and are pectinate in a few Chalcidoidea. The ovipositor in some groups (a) rises anterior to apex of the abdomen (on the ventral side) and is more or less permanently extruded, and usually cannot be withdrawn into abdomen. In other groups (b) the ovipositor issues from apex of abdomen and is withdrawn when not in use. Apocrita with an ovipositor of the 1st type (a) usually do not sting; those with an ovipositor of the 2nd type (b) usually do. Trochanters may be 1- or 2-segmented. Venation varies from almost no veins to a maximum of 10 closed cells in front wing (see p. 313). If there are at least 6 closed cells in the front wing the venation may be described as "normal"; if there are fewer, it may be described as "reduced."

Larvae of Ichneumonoidea, Evanioidea, Pelecinoidea, Bethy-

SUPERFAMILIES OF APOCRITA 319

ovipositor

Characters of the Superfamilies of Apocrita

Character

Ichneumonoidea

Chalcidoidea

Cynipoidea

Evanioidea

Pelecinoidea

Proctotrupoidea

Bethyloidea

Scolioidea

Vespoidea

Sphecoidea

Apoidea

Pronotum1

a

b

a

a

a

a

a,b

a,b

a

c

c

Ovipositor1

a

a4

a

a

b

b

b

b

b

b

b

Sting

no4

no

no

no

no

no

yes4

yes4

yes

yes

yes4

No. of hind trochanter segments

0 0

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