THE CANADIAN ENTOMOLOGIST. 45 



preferred indigenous food-plant has not been associated with it, and its 

 range is surely of a northern character. Its prevalence in Arctium was 

 very marked in the season of 1909, all undisturbed waste places, even in 

 the heart of the city that are productive of this weed seem to support 

 flourishing colonies. Cataphrada and necopina occur with it in much 

 less numbers, but the work oi arctivorens is confined more particularly to 

 the top of the plant. It prefers to pass most of its period in the parts at 

 the head of the main stem or branches, which produces a more or less 

 aborted growth. At the middle of July the midday sun causes a notice- 

 able wilting of the growth above the cell-like boring, and as several 

 examples are often in one plant, the effect becomes marked. Mr. A. F. 

 Winn, who, among other of the Montreal collectors, has had the species 

 long under notice, years ago coined the term "hydroecitis" for this appear- 

 ance of the plants. Of his interesting observations he has seen the newly- 

 emerged larva ascending the plants and drilling its way within the stem, 

 and has drawn our attention to a parasitic wasp, which is an additional 

 species as effecting this genus. 



Ova were secured Sept. 6 from a pair confined in a roomy vivarium. 

 They were deposited scatteringly without apparent design, singly or in 

 small clusters. The egg is slightly flattened, the greatest diameter .6 mm., 

 colour yellowish pearly-white. They winter over and emerge the latter 

 part of May. 



Stage I. — Generic characters fully evident, the dark middle joints, 

 four to eight, are crossed by the continuous whitish dorsal line, the sub- 

 dorsal being here discontinued ; tubercles and setae pronounced, the latter 

 on abdominal joints one, two and three appear longer than the others ; 

 true legs black ; spiracles ringed with black ; head and shields shining 

 yellowish. 



Stage 11. — Similar to preceding, the darkened portions become 

 darker now, a deep purple-lake, the lines purer white. Tubercle IV 

 becomes larger on abdominal joints. 



Stage III. — As before; head and thoracic shield of equal width, 

 polished, yellowish, a black line from the ocelli crosses the epicraneum 

 obliquely to lower edge of shield, which is here bordered with black ; 

 tubercles blacker. 



Stage IV. — Colours as before ; the first pair of abdominal legs are 

 still shorter, but now used ; the blackish line on head and lower edge of 

 shield finds continuation in the dark body colour existing as a stripe on 



