PROCEEDINGS, 1917 17 



The above three insects were described in the Can. Ent.. \'o!. 

 XL VIII., page 249 et seq. (July. 1916). 



The next in order is the genus Xanthorhoe, a genus we have been 

 working on for some considerable time. When I started to collect 

 geometers seriously in the spring of 1912, I was much struck with the 

 amount of variation that occurred in three species of this difficult but 

 interesting genus. I determined to pay special attention to this group, 

 with the result that in 1913 and 1914 I collected something over 300 

 specimens of this genus. The three groups mentioned are the defensaria 

 group and what are known as the fossaria-pontiaria group and the 

 munitata-convallaria group. 



Taking the defensaria group first, I sorted them out into series gov- 

 erned by the date of their appearance and the differences in maculation. 

 I then sent them to Mr. Swett, who agreed in the main with my separa- 

 tion, with the result that the following four well-marked varieties were 

 described by him in the Can. Ent., Vol. XLVIIL. page 349 et seq. 

 (October, 1916). 



X. defensaria var. gigantaria Swett, which is the large spring form 

 occurring at the end of April. It is distinguished by its large size, heavy 

 markings, and wide bands. 



X. defensaria var. conciliaria Swett. This is a very distinct form 

 and is easily recognized by the basal and outer areas of the fore wings 

 being a deep ochre and the median band of a reddish chocolate colour. 

 It flies along with, and at the same time as, typical defensaria. 



X. defensaria var. thanataria Swett. This is a small and stunted 

 form which occurs later in the fall, generally in September and October. 

 It is possibly a third brood, but this cannot be definitely stated until it 

 is bred. In fact, the whole of this group may have to be revised again, 

 when the life histories of the various forms are worked out and the 

 genitalia studied. 



X. defensaria var. suppuraria Swett. This is a beautiful variety 

 and a very distinct one, the broad black band contrasting sharply with 

 the lighten ashen colour of the fore wings. This median band is subject 

 to a variation in colour from reddish black to a deep jet black, and is 

 really a melanistic form. This is the rarest of all the varieties and occurs 

 in April. 



I may say here that the study of the fossaria-pontiaria group has 

 just been completed and three new species have been discovered, which 

 will be described in the Can. Ent. at an early date. This leaves us the 

 munitiata-convallaria group to work on during the present year, and 

 Avhich we hope to complete before our next annual meeting. 



We now come to the Dysstroma citrata-mulleolata group. Citrata 

 Linn and its varieties I treated of in our Proceedings No. 4, N.S., page 

 44 et seq., 1914, and mulleolata I spoke of in the paper I read before you 



