Platypus parallelus (F.) apparently is the most destructive ambrosia beetle in the 
world. Although it occurs in Florida, Texas, and southern California, the unfavora- 
ble climate prevents this tropical species from becoming sufficiently abundant to 
cause more than minor damage to hardwood trees in North America. 
Ambrosia beetle control is largely a matter of preventing damage to recently cut 
logs through quick removal from the woods, proper storage of logs at the mill, and 
by proper handling of lumber and milled products (76). 
Order Hymenoptera—Ants, Bees, Sawflies, Wasps, 
and Allies 
The order Hymenoptera is one of the largest orders of insects, with more than 
20,000 species in America north of Mexico. Most are beneficial and many are very 
important to forestry and agriculture either as parasites or predators of pests or as 
pollinators of more than 100 commercially grown crops. The honey bee is one 
important pollinator. Among the relatively few injurious Hymenoptera are the 
sawflies, some of which are stem borers attacking crops or serious defoliators of 
coniferous trees (697). 
The winged members of the order characteristically have four membranous 
wings, the front pair larger and more completely veined than the hind pair. The 
hindwings have a row of tiny hooks along the anterior margin by which they are 
attached to the forewings. Some forms, or groups, such as workers of the common 
ant, are wingless. The ovipositor is usually well developed and in the higher forms 
is modified into a sting. 
The order is divided into two suborders—Apocrita (= Clistogastra) and Sym- 
phyta (= Chalastogastra) (697). Each of these, in turn, is divided into a number of 
superfamilies. 
Suborder Symphyta (= Chalastogastra) 
Members of the suborder Symphyta are distinguished by having the abdomen of 
the adult broadly joined to the thorax—the second abdominal segment is not 
constricted into a petiole as in the suborder Apocrita. The ovipositor of the female 
is well developed and fitted for making incisions in the leaves or stems of plants. In 
the majority of species it is sawlike. Because of this, these members of the suborder 
are known as sawflies. 
The larvae of all species, except for the family Orussidae, are phytophagous, the 
majority feeding externally on the foliage. The remainder bore into stems, fruit, 
wood, or leaves, and some form galls. Orussid larvae are parasitic on wood-boring 
coleopterous larvae. While externally leaf-feeding larvae look like lepidopterous 
larvae, they have only one simple eye on each side of the head and have six or more 
pairs of prolegs on the abdomen, none of which bears hooks or “‘crochets.” 
The suborder Symphyta is represented in the United States and Canada by more 
than 1,000 species, many of which are highly destructive of forest and shade trees 
and of young trees in nurseries and plantations. 
Superfamily Megalodontoidea—Family Xyelidae 
Xyelids 
Members of the family Xyelidae are medium-size to small sawflies, mostly less 
than 19 mm long. They differ from all other sawflies in having the third antennal 
segment elongate with a slender terminal filament of 9 to 25 segments, and in 
having three marginal cells in the forewing. Unlike all other sawflies except the 
Pamphiliidae, they have the costal cell divided by a longitudinal vein. 
SW 
