60 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 
Hapsit oF LIFE. 
While the vast majority of the Chalcididae then are parasitic 
on insects, there are some which have a phytophagic or 
vegetarian habit. Over half a century’s controversy has taken 
place regarding this phytophagic habit, but now entomologists 
are agreed that in the genus /sosoma and closely-allied genera 
at least, vegetable-feeders are found. 
THE Genus ISOSOMA. 
Scattered up and down in entomological writings in the 
United States and Canada, from 1834 onwards, are observations 
by Harris, Fitch, Cadell, Walsh, Pettit, Riley, and Howard on 
the food-habits of /sosoma.1 Howard gives the date 1882 as 
the time by which all entomologists were agreed as to the 
phytophagic habit of /sosoma. 
Recently Mr F. M. Webster? has enumerated sixteen North 
American species of /sosoma whose larve are directly injurious 
to wheat, barley, rye, or other grasses. 
An interesting feature in the biology of the Greater Wheat 
Straw-Worm is chronicled by Webster, this species showing in 
its life-history an alternation of generations—a spring generation, 
wingless and small in size, alternating with a winged summer 
generation larger in size. The importance of a knowledge of life- 
history is well illustrated here, for as the spring generation is 
wingless it can be fought by changing the crop. 
The following three genera, related to /sosoma, are stated by 
Howard, from notes in the Division of Entomology of the United 
States, to be gall-makers—LZurytomacharis, Ash., Lsomorpha, Ash., 
and Philochyra, Hall. 
Outside of American literature we have various records. West- 
wood, in the Gardeners’ Chronicle, 1869, records a Chalcid, the 
pupz of which he took from an orchid. Certain curculionid grubs 
were feeding on the orchid leaves, but Westwood, believing that 
the Chalcid had been feeding not on these grubs but on the plant 
itself, suggested for the Chalcid the name /sosoma orchidearum. 
1 Formerly several of the forms now named /sosoma were named as of the 
genus Lurytoma. 
2 U.S. Department of Agriculture, Division of Entomology, Bull. No. 42, 
1903—Some Insects attacking the Stems of Growing Wheat, Rye, Barley, 
Oats. By F. M. Webster, M.S. 
