280 THE CANADIAN ENTOMOLOGIST. 



they are now so few and far between that it requires some search to find 

 one. I was particularly struck with the difference, in this respect, 

 between this section and the Atlantic slope, on my journey to Washing- 

 ton last August, the eastern woods and orchards being in many places 

 almost defoliated and presenting a very unhealthy and unsightly 

 appearance from the ravages of this insect. 



It is impossible, of course, to ascertain just when or how the beetle 

 under consideration acquired the habit of preying upon the Web-worm ; 

 but I think it could not have been much previous to its discovery. In 

 1888 Hyphatitria was abundant in Kirkwood, and for the purpose of 

 obtaining fresh specimens of the moth, as well as of its usual parasites, I 

 transferred a colony from a box elder tree to the rearing cage. PYom 

 these a large number of perfect insects were bred and also parasites of 

 \.NO or three species, but no larvae or imagines of Plochionus were 

 observed. 



Early in June, 1890, I had been struck with the wasting away of one 

 or two colonies of Hyphantria and was about to examine into the causes, 

 when I received from Mr. J. C. Duffey, the Horticulturist of the Shaw 

 Botanical Garden, a note informing me that larvae of a small carabid had 

 been found in a nest of Web worms, upon which they were evidently 

 feeding. Accompanying this communication was a box containing one 

 of the infested colonies. Unfortunately the box had been broken in 

 transit, and when I called for my mail the Web-worms were pervading 

 the office, and the distracted postmaster was engaged in a vain attempt 

 to confine them in a newspaper, and expressing himself with some 

 emphasis concerning the sort of mail posted by entomologists. Un- 

 doubtedly many of the predaceous larvae escaped with the caterpillars, 

 but upon examination, after reaching my study, I found seven or eight of 

 the larvae in the fragments of the web and a sufficient number of Web- 

 worms to afford them sustenance. Placing them on fresh leaves in a small 

 rearing cage on my desk, I soon had ocular verification of Mr, Duffey's 

 interesting observations. 



The Hyphantria larvae had all passed the last moult and many were 

 nearly full grown ; the carabids were also nearly mature, varying in 

 length from one-fourth to one-third inch, somewhat alligator-shaped, the 

 head provided with sharply pointed trophi, with rather long and strong legs, 

 the body above dark and horny ; they had quite a formidable aspect. By 

 preference this larva attacks its victim from the front, biting into the 



