316 THE ENTOMOLOGIST. 



a small spider the exact colour of uncooked meat, which, in 

 the same way, had entrapped two hive bees by lurking 

 within the blossoms of Cnicus pratensis, from which it was 

 undistinguishable in colour, and thus the unwary bees had 

 visited their accustomed haunts, little thinking of the deadly 

 enemy which awaited them therein. T presume that all these 

 three instances are cases of "mimicry." 1 shall gladly send 

 you the flowers, the spiders and the bees, if you think it 

 worth the trouble of seeing them. — C. TV. Penny; Welling- 

 ton College, Wokingham, May 15, 1871. 



I am greatly obliged by the offer of the insects and 

 flowers, but I have seen so many similar instances that I 

 require no ocular proof of the facts related. There can 

 scarcely be a doubt that the colour of the spider is for the 

 purpose of concealment, but it is not, as is so commonly the 

 case, protective. The tendency of concealment in these 

 cases is rather destructive than protective, at least in the case 

 of the bee. 



Works on Coleoptera and Diptera. — Is it your intention 

 to bring out a book on either of these classes? as I am sure 

 it would meet with as enthusiastic a reception as y^our 

 Lepidoptera has already received. — S. T. Klein ; Haileybury 

 College, Herts, May 1,1871. 



I have no such intention ; and I rather doubt the enthu- 

 siastic reception. Diptera are especially unpopular. 



Error in British Moths. — Have not you got Plusia 

 chrysilis figured as Festucae, aud vice versa ? — C. E, Hol- 

 ford ; High Oak House, near Ware. 



I think you will find this — which is a printer's, not 

 an author's, mistake — corrected in p. 476 of the same 

 work. 



Gall on Salix nigricans. — A beautiful gall, of a bright 

 scarlet colour and spherical form, occasionally makes its 

 appearance on the upper side of the leaves of the black 

 willow, always singly, and of that uncertain size generally 

 compared to a pin's head. A specimen has been examined 

 by one of our best-instructed students of this family of 

 veget*able productions, Mr. H. W. Kidd, of Godalming, and 

 it proves to be quite unknown to him. Can any other 

 correspondent give it a name ', the description, however im- 

 perfect, will distinguish it from all the other galls occurring 



