4 Hymenoptera in America North of Mexico 



drous in the Macroxyelinae and strophandrous in the Xyelinae. 



All members of this suborder are phytophagous except for the family Orussidae which is 

 parasitic on other wood-boring insects. Host plants and habits are various. Many larvae are ex- 

 ternal feeders on the foliage of the host, but others are leaf miners, gall formers on twigs, 

 petioles, leaves, or buds, leaf-edge rollers, stem borers, wood borers, or petiole miners. Because 

 of their plant feeding habits, many sawflies are pests of ornamental plants, agricultural crops, or 

 forest stands. Their occurrence is normally local, but outbreaks in forests may be extensive, 

 covering many thousands of acres and resulting in considerable growth loss or death of trees. 

 Appearance in epidemic proportions is commonly sporadic, suddenly appearing for a year or 

 more then practically disappearing for several years, probably being kept under control by their 

 natural parasite-predator-disease complex. Some of the most destructive species are aliens 

 which were accidentally introduced from abroad and found a vacuum for development without 

 natural enemies. Many parasites have been introduced to help combat these pests. Some of the 

 more important sawflies are those that feed on timber species, roses, apples, pears, peaches, and 

 wheat and other grain crops. On the other hand, a few sawflies have been used beneficially, or at 

 least have been attempted for use in the biological control of weeds. One species, Ucona acaenae 

 Smith (=Antholcus varinervis of authors), was introduced into New Zealand from Chile in the 

 early 1930's to help control the spread of Acaena. This attempt was only partially successful. 

 Another species, Priophorus morio (Lepeletier), was released in Hawaii from the western 

 United States to help control the spread of Rubus on the islands, but this attempt failed. 



The life cycle of many sawflies follows a similar pattern, though with many variations. Adults 

 of most species fly in spring and early summer and are very short-lived. It is difficult to keep in- 

 dividual adults alive in captivity for much more than a few days although the actual flight of a 

 species may extend over several weeks or months. Some adults may not feed but some may feed 

 on moisture, nectar and pollen of flowers, leaf pubescence, or other insects. The most productive 

 areas for collecting are in vegetation on edges of rivers or streams, marshes, open and scrubby 

 woodland, or undisturbed meadows. The catkins of willows and alders are especially productive 

 for many groups. Oviposition is in the foliage, stems, twigs, or wood, and the eggs are most al- 

 ways inserted in the plant tissue though some Pamphiliidae may glue their eggs to the leaf sur- 

 face. Larval feeding time varies, but usually lasts about two weeks. Many larvae, especially 

 Diprionidae, feed gregariously at first but later disperse to other parts of the host. After feed- 

 ing is completed the larva molts into a non-feeding stage called the prepupa or resting stage. 

 The prepupa normally leaves the host in search of a site for pupation. This may be in a cell in the 

 ground or litter, in a papery cocoon in the ground, in some other substance such as wood, stems 

 of the host or nearby plants, or fruits of other plants. The prepupal stage differs morphologically 

 from the feeding stages, especially in the shape of the mandibles and sometimes color pattern. 

 Some larvae with spines loose these in the final molt. If there is a single generation, the prepupa 

 will remain in its cocoon or cell the rest of the summer and pupate the following spring. How- 

 ever, depending on the species, latitude, or diapause requirements, there may be several genera- 

 tions a year, or it may take several years to complete the cycle. 



The following references are to general articles on the Symphyta. Some, such as Maxwell, 

 1955, in morphology, pertain to many species and the reference is not repeated under each spe- 

 cies. Under some species, such as Pristiphora erichsonii (Hartig), a listing of all biological 

 references would take many more pages, and the references are selected or pertain to some 

 recent synopsis which contains a good bibliography. Some of the new distribution records, hosts, 

 and taxonomic changes are taken from unpublished notes. Only those taxonomic changes cited as 

 being new have not before appeared in the literature. 



I am indebted to several colleagues for reviewing parts of this section and or providing some 

 of the information contained herein: H. E. Milliron, formerly with the Biosystematics Research 

 Institute, Agriculture Canada, Ottawa and other authorities of the Institute for allowing study 

 of their sawfly collection; H. R. Wong, Northern Forest Research Centre, Canadian Forestry 

 Service Edmonton, Alberta, Canada; and H. Greenbaum, Department of Entomology, University 

 of Arkansas Fayetteville. 



Taxonomy: Norton, 1867-1869. Amer. Ent. Soc, Trans. 1: 31-84, 193-280; 2: 211-242, 321-368 

 (N. Amer. catalog). — Cresson, 1880. Amer. Ent. Soc, Trans. 8: 53-68 (N. Amer. catalog). 

 — Dalla Torre, 1894. Cat. Hym., v. 1, 459 pp. (world catalog). — Ashmead, 1898. Canad. Ent. 

 30: 141-145, 177-183, 205-213, 225-232, 249-257, 281-287, 305-316 (classification, keys to 



