1923 ENTOMOLOGICAL SOCIETY. 33 



pomus) the larvae feed upon aphids which are exposed to the sun, (Aphis pomi) 

 and are unique in this respect as Syrphid larvae rarely are able to survive under 

 such conditions, but must seek the shade of a leaf or stem. The adult is small 

 and dark in colour as compared to the typical form (S. americanus). The 

 other form (S. americanus vinelandii) has a green larva while that of americanus 

 is greyish yellowish. While there are evidently three distinct species, it was 

 considered advisable to consider them merely as varieties. I cite here only the 

 one instance, where such a condition occurs in our Syrphidae, as an illustration 

 of the problems confronting the student and the need of further study. I might 

 point out that Barnes and McDunnough (Mem. Am. Mus. Nat. Hist., Ill, 

 Pt. 1, p. 4) have found that they have been unable to definitely satisfy them- 

 selves as to the limits of certain species of Catacola without referring to the 

 biological peculiarities and distinctions. 



I have dealt in more detail, in a paper which will be published within the 

 next few months, with the influence of larval food upon the appearance, habitus 

 and deportment of the adult insect and therefore feel that the subject may be 

 lightly dealt with here. I may say that is very often possible to ascertain by 

 the appearance of an imago, whether the larva is predaceous, parasitic or a 

 scavenger, omitting entirely our knowledge of the habits of the species or genus 

 as conveyed by familiarity with it. Such a thing is possible because the larval 

 habits have influenced the adult to develop along definite lines. With the aphid 

 feeding forms the adult has a compressed, light abdomen, or a long slender one, 

 due to the relative paucity of food, the thorax is large and well supplied with 

 muscles and the head large, the eyes being unusually well developed, apparently 

 in order that the insect may readily discern aphids and deposit their eggs. On 

 the other extreme the forms living in liquid media are robust, the head is relatively 

 smaller, and while they are also excellent hoverers, they have a much stronger 

 wing venation in order to carry their weight. Those living in decaying wood 

 are, generally speaking, intermediate; while predators and parasites all have a 

 quite different shape of abdomen, with the exception of Tachinids, which really 

 are allied to those living in liquid media because of the succulence of the larval 

 host. 



INSECTS OF THE SEASON IN ONTARIO 

 L. Caesar and W. A. Ross 

 Orchard Insects 



Codling Moth (Carpocapsa pomonella). In orchards east of Toronto and 

 also around Burlington there was more than the usual amount of loss from side- 

 worm injuries, Kings in some orchards having as high as 50 per cent, of injury 

 and Snows 30 per cent. In Niagara, Norfolk and several other districts the 

 amount of injury of this kind was not nearly so great and was scarcely up to 

 the average. 



Fruit-Tree-Leaf-Roller (Tortrix [Cacoecia] argysrospila) . There was a 

 considerable diminution in the numbers of this troublesome insect this year 

 compared with the years 1920 and 1921. 



Apple Maggot (Rhagoletis pomonella). From Burford very badly infested 

 apples were sent in with the statement that some varieties had been almost 

 ruined by this insect. Taking the province however, as a whole our observations 

 tended to show that the apple maggot had not done so much damage as it 

 often does. 



2 E.S. 



