CATALOGUE OF BUTTEE FLIES. 5 



yellow and White Butterfly," who adds, '' it is one of our first 

 Butterfly visitants in the spring, making its appearance in May." 

 This year (1857) on the 4th June, in the vicinity of Callaly, I 

 observed its simultaneous occurrence in great numbers through- 

 out that district where not a single one was to be seen the 

 previous day — a striking, but not infrequent incident amongst 

 the Diurnal Lepidoptera." 



'' The usual expansion of the wings is 1-8" to 1-11", but in the 

 year 1832 none exceeded 1*3", and so marked was the diiference 

 all over the country that many were inclined to consider the 

 specimens as those of a distinct species. The following season 

 there was no departure from the normal size." (Wailes' Cat. 

 Lep. Korthd. and Durham, p. 8. Trans. Tyneside Nat. Field 

 Club, vol. 3, 1858). 



Eor some years this pretty species all but disappeared from 

 our district, but it has resumed its usual numbers again. The 

 disappearance was simultaneous with that of the other species, 

 which will be noticed in their places. It is not very unusual 

 for exceedingly small specimens to occur. I have examples of 

 both sexes in my cabinet which do not exceed one inch in 

 expanse. 



Cardamines is remarkable for what is now called ''mimicry," 

 which obtains in every state. Mr. Barrett describes the pupa 

 as ''forming an obtuse projecting angle, which fits well to the 

 underside of the insertion of a side shoot of the food-plant, so 

 that it is hardly distinguishable from a thickening of the stem. 

 Indeed this species exhibits a series of curious adaptations to its 

 surroundings, the larva being so like a seed-vessel as almost to 

 defy detection, the white line down its side actually simulating 

 the line of light down the side of the glossy seed-vessel, and the 

 Butterfly, when in repose, with closed wings, on the tip of a 

 flower spike of Cardamine pratensis — a favourite resort — seems 

 at first sight a mere continuation to the bunch of buds ; whilst 

 its accurate adaptation to the leaf of one of the smaller Umhel- 

 liferce, upon which also it commonly rests, is notorious. Such 

 accurate mimicry in three stages of the life of the same insect 

 is truly marvellous." Barrett, Lep. of the British Isles, vol. 1, 

 p. 30. 



