7 



The insect world is composed of myriads of specimens which from their varied struc- 

 ture and habits admit of being classified into families, each distinct and usually easily re- 

 cognizable to the practiced eye of the Entomologist. A large portion of this innumerable 

 host is appointed to prey upon and devour the other portions, and thus it appears to me, 

 that apart from any consideration of insectivorous birds, the insect world would and 

 does, to a large extent, take care of itself, and when an injurious species increases beyond 

 its normal limits, its natural insect enemies, having an unusual amount of material to work 

 on, soon become sufficiently numerous to reduce the number of the injurious insect to its 

 normal proportions again. As an illustration, take the now common cabbage butterfly, 

 Pieris rupee. This insect was in some way brought from Europe to Quebec a few years 

 ago. From Quebec it has since spread over an immense area extending now from Ala- 

 bama to the waters of Lake Superior, eastward to the Atlantic, and westward many 

 hundreds of miles, and over all this district it has done immense damage to the cabbage 

 crop. Throughout this area insectivorous birds of all sorts prevail ; the butterfly is con- 

 spicuous, not very strong in flight, and during the day almost constantly on the wing ; the 

 larva feeds in exposed situations, is of that smooth character which birds are said 

 to prefer, and although similar in colour to its food plant, is not difficult to detect. 

 Here, then, is an instance where a comparatively feeble insect, particularly vul- 

 nerable to attack, has rapidly spread over a large portion of this continent, with little or 

 no opposition from insectivorous birds. Indeed 1 have never yet found or known to be 

 found a single example either of the butterfly or its larva in the stomach of any 

 bird. In its native home in Europe it is seldom so very destructive as here, for 

 the reason that a small four- winged fly, Pteromalus puparum, an insignificant look- 

 ing little creature, is a parasite on the larva of this butterfly, and hunts its vic- 

 tims with the greatest assiduity ; alighting on their backs and thrusting its slender 

 ovipositor through the skin of the larva, it deposits a number of eggs there, which hatch 

 into tiny grubs, and those feed upon and eventually destroy the caterpillar. By the con- 

 stant efforts of this little parasite the cabbage butterfly is prevented in Europe from be- 

 coming a very serious pest. Fortunately this little friend has also been introduced here 

 from Europe, although in what manner is not known, and is rapidly spreading, following 

 in the wake of its prey, and where the parasite has fairly established itself, this butterfly, 

 with its numerous progeny of green caterpillars, soon dwindles in numbers so materially 

 as shortly to cease to be so grievous an evil. The butterfly spreads faster than its enemy 

 and is usually several years in advance of it, but we may confidently anticipate that 

 sooner . or later this small fly will do for us what it has done for Europe — keep this 

 troublesome insect within due limits. Many other similar examples might be given. 



Further, the help of friendly parasitic insects is so much more efficient because it is 

 in most instances discriminating. As far as is known, the little parasite referred to 

 attacks only the larva of the cabbage butterfly, and in like manner many other parasitic 

 species are restricted in their operations to a single species, while in other instances they 

 are confined to a genus or a group of similar species. This is not so with insectivorous 

 birds ; they in most instances devour alike the useful and the injurious species, and the 

 question may well be raised in many instances whether the good they do is not more than 

 counterbalanced by the number of useful insects they devour. Recent observations on 

 the family of thrushes, by Mr. S. A. Forbes, of Illinois, seem to show that their insect 

 food consists largely of beetles belonging to the Carabidce, a family every member of which 

 is useful, since they, as far as is known, feed both in the larval and beetle states exclusively 

 on other insects. 



The field here open is a wide and inviting one, on which I trust some of you will 

 enter. I have but touched upon it ; as the results of more extended observations are 

 recorded the opinions here expressed may need modifying. I desire to do justice to the 

 birds. 



During the month of August last, it was my privilege to visit the Great Manitoulin 

 Island, also Sault Ste. Marie and the district adjoining. Although prevented by an acci- 

 dent from indulging in free locomotion, still I saw much that interested me. On Mani- 

 toulin Island I found many of the species of butterflies common in the more southern 

 portions of Ontario ; a few moths were also captured. On the shore of Elizabeth Bay, 



