10 



BULLETIN 265, U. S. DEPARTMENT OF AGRICULTURE. 



THE ADULT. 



The adult sawfLy (fig. 3; PI. I, fig. 3) is a slender, blue-black, wasp- 

 like insect, with reddish legs. Ab first glance it may be mistaken for 

 an ichneumon fly, but it will be distinguished readily by its thicker 

 and heavier abdomen, its relatively shorter antennas, and in the female 

 by its lack of the usual long, conspicuous ovipositor of the ichneumon 

 fly. The males and females are similar, the males averaging smaller. 

 The description given for Taxonus rdgrisoma by Norton (8) character- 

 izes the adult very well, and is given herewith : 



Blue black, the legs dark rufous; length 0.30, breadth of wrings 0.60 inch. Color 

 blue black; abdomen rather long, flattened, acute; antennae slender, basal joint en- 

 larged, third longer than fourth; apical joint as long as the preceding; clypeus angulate 

 emarginate; labrum and base of mandibles pale rufous; legs rufous or honey yellow; 

 base of coxae and tarsi black; wings faintly clouded, stigma and costa black. 



Fig. 3. — The dock false-worm: a, Adult fly, twice enlarged; b, adult female, much enlarged; c, anal 

 segments of female showing OA'ipositor; d, tarsus of hind leg of female. (Original.) 



LIFE HISTORY AND HABITS. 



METHODS OF STUDY. 



In studying the life history of the dock false-worm, rearings were 

 made in an outdoor insectary with a roof but no sides. In order to 

 rear the larvae under conditions as nearly normal as possible, they 

 were kept on living plants. Small plants of the common curly dock 

 (Rumex crispus) and of the wild buckwheat {Polygonum convolvulus) 

 were potted in tin cans. After being kept in a cool place for a 

 few days, with plenty of water, these plants appeared normal and 

 made regular growth throughout the season, some of them even 

 producing flowering stalks. The dock plants were by far the most 



