1924 ENTOMOLOGICAL SOCIETY . 57 



what may be considered biological races, but our knowledge of insects is so 

 meagre in comparison to what is to be learned that we are not able, at the present 

 time, to arrive at positive conclusions as to the status of certain forms. We 

 •know that many species are much more easily separated in the larval than 

 imaginal stage and it therefore seems possible that many insects may be most 

 readily determined by their host, and that careful study will reveal imaginal 

 distinctions not previously suspected. 



The three species of Rhagoletis which have been included under pomonella 

 may be separated as follows: 



R. pomonella. (Male) Genital claspers, as in Figs. 2 and 2a. The lobe of the 

 clasper opposite the hooks is almost transverse towards the base of the clasper 

 and the hooks are longer, the lower hook being much more evidently curved; 

 the spot on the scutellum usually occupies the apical half and extends on the 

 disc, well beyond the apical bristles; size usually over 4 mm. (Female) The white 

 scutellar spot occupies two-thirds or more of the length of the scutellum and is 

 very prominent to the naked eye. Size usually over 4.5 mm. 



R. symphoricarpi. (Male) Genital claspers, as in Figs. 1 and la. The shapes 

 of the parts as well as of the clasper itself are quite different, the hooks are 

 shorter, the lobe tapers towards the base of the clasper, which is always less 

 curved, wider and more compressed beyond the hooks; the spot on the scutellum 

 is much smaller and usually does not extend very much laterad of the apical 

 bristles; size seldom over 3.5 mm., usually slightly less. (Female) The white 

 scutellar spot seldom occupies more than the apical half of the scutellum and 

 is usually very distinctly narrower than in pomonella; length 3.5 to 5 mm., the 

 average length slightly over 4 mm. 



R. zephyria. (Female) The scutellar spot occupies less than the apical half of 

 the scutellum and reaches well laterad of the apical bristles. The paler lateral 

 margins of the front at the middle extend as far inside the frontal bristles as 

 the distance from the base of the bristles to the orbit. In both the preceding 

 species the pale stripe scarcely extends inside the base of the bristles and these 

 are also slightly closer to the orbit. 



I must confess that the differences enumerated as separating the first two 

 species, except those of the hypopygium, appear slight. However, they are 

 rather constant. R. zephyria is more readily distinguished in the female sex 

 than are the other two. 



It would be very interesting to know the host of R. zephyria, but we have 

 no indication. A strange thing about symphoricarpi is that the first two speci- 

 mens were taken by Mr. Treherne on the leaves of apple in an orchard. 



INSECTS OF THE SEASON 



W. A. Ross, Dominion Entomological Laboratory, Vineland Station, 

 and L. Caesar, Provincial Entomologist, O.A.C., Guelph 



Orchard Insects 



Codling Moth (Carpocapsa pomonella). Side-worm injury was again quite 

 severe in several sections of the Province; whereas in other parts such as in 

 Norfolk County the injury was negligible, even in orchards which were only 

 sprayed once for codling moth control (post-blossom application). 



