THE CANADIAN ENTOMOLOGIST. 281 



under part of the thoracic segments ; but in many cases I have seen it 

 seize hold of the side of a caterpillar, into which it would soon almost 

 bury its head, and not the most violent contortions on the part of its 

 prey were of avail to dislodge it. By the time its appetite was appeased 

 the Web-worm would be fatally injured, and a fresh one would be required 

 for its next meal. In this way one beetle larva was capable of destroying 

 a great number of the worms in the course of its development. The two 

 species, web-worm and carabid, reach maturity about the same time, the 

 period of carabid adolescence being about one week less than that of the 

 insect on which it preys. The change to pupa takes place both on the 

 surface of the ground and in the remnants of the web on the tree — in the 

 latter case it (being very soft and white and not enclosed) is subject to 

 destruction by birds and other insects. The beetle appears in from eight 

 to ten days after the change to pupa, and requires a day or two to 

 acquire its dark brown colour and the firmness in texture of maturity. It 

 is very swift and furtive in its movements and remains hidden as far as 

 possible during the daytime, but is, even in the rearing cage, quite active 

 at night, using its wings freely. It feeds, sparingly, on aphides and similar 

 soft insects. This season I found it in considerable numbers in the two 

 web-worm nests that occurred in our orchard, and to test its destructive 

 capacity I placed thirty-six three-fourths grown Hyphantria larvae in a 

 large glass jar, with three nearly mature Plochionus larvae. A large 

 number of the caterpillars were killed in the course of the following week, 

 and from the three dozen larvae I bred seven parasites ( Meteonis 

 hyphantria) and but three moths ; the remainder had evidently succumbed 

 to their coleopterous foes, all three of which developed into fine beetles. 



In respect to Mr. Duffey's wish to present the first published account 

 of this insect, I refrained from mentioning it to the Club at the 

 Indianapolis meeting, but referred to its valuable services in my notes for 

 the Division of Entomology of the same year. Early in the autumn, 

 1890, Mr. Duffey read a paper on this insect and its interesting habits 

 before the Academy of Science of St. Louis, giving its history somewhat in 

 detail, and also technical descriptions of the adolescent stages, accom- 

 panying these with some tolerable illustrations. This paper was published 

 in the Transactions of the Academy the following February, and renders 

 it unnecessary for me to describe the larva and pupa more minutely. 



I believe the perfect insect occurs sparingly in many sections of the 

 country, but it may not in every locality acquire the habit of preying on 



