INTERRELATIONS OF INSECTS srl 
though some are phytophagous, for example, /sosoma hordei, 
which lives in the stems of grasses, especially wheat, rye and 
barley. Chalcids affect a great variety of insects of one stage 
or another, such as caterpillars, pupz, cockroach eggs, plant 
lice and scale insects; while some of them develop in cynipid 
galls, either upon the larvee of the gall-makers or upon the 
larve of inquilines. Giard in France reared more than three 
thousand chalcids (Copidosoma truncatellum) from a single 
A tomato worm, Philegethontius sexta, bearing cocoons of the parasitic Apanteles con- 
gregatus. Natural size. 
caterpillar of Plusia. Proctotrypidze are remarkable as para- 
sites. Most of them are minute; indeed this family and the 
coleopterous family Trichopterygidz contain the smallest 
winged insects known—species but one third or one fourth 
of a millimeter long. A large proportion of the Proctotry- 
pide are parasitic in the eggs of other insects or of spiders, 
several sometimes developing in the same egg; others affect 
odonate nymphs and coleopterous or dipterous larvee, while 
several species have been reared from cecidomyiid and cynipid 
galls, and many proctotrypids are parasites of other parasitic 
insects—in other words, are /iyperparasites. 
