1864.] 613 



mystery was partially solved. I found September 26 in a great many 

 of their nests numerous Rliophigaster n. sp. (?) (JJeteroptera), both 

 in the pupa and imago states, along with great quantities of their ex- 

 uviaj ; and suspecting them to be there on no friendly errand, I con- 

 fined four of them in a breeding-jar, where I had a large brood of 

 young Arctians raised from a mass of eggs and feeding on wild mul- 

 berry leaves. Within the next few days T had the pleasure of seeing 

 one of them, on two separate occasions, with its beak porrectand plunged 

 into the body of an unfortunate Arctian larva, and the sucked carcass 

 of another one lying by its side. I had previously in August found 6 

 or 8 Tetyra fimhriata Say in the web-nest of another lepidopterous 

 larva. Hence I infer that Snttelleridae are generally insectivorous; for 

 the Rliaphigaster had evidently, from the numbers of their exuviae, 

 been inhabiting the nests of H. textor for a long time. Some instances 

 of their insectivorous habits are recorded by Westwood. though he 

 states al-so that they live upon sap, "introducing their rostrum into 

 leaves," which I have never seen them do. {Litr. IT. p. 486.) 



So much for the " Curl" on Peach-trees. There is another gall-like 

 excrescence popularly known as the " Black-knot," and very abundant 

 on the wild and cultivated Plum and occasionally found on the Cherry, 

 which has been a similar Crux Entomologorum. T'nlike the "Curl" this 

 is just as common in the Valley of the Mississippi as it is said to be in 

 the Eastern States, but I have never watched it through the earlier 

 stages of its progress, and know it only in the mature and dry specimen. 

 Dr. Fitch describes it as " commencing upon the small limbs, and to be 

 recognized at first by a slight swelling of the bark on the upper side of 

 the limb, which begins in autumn and remains stationary through the 

 winter. In the spring this swelling increases, rupturing the cuticle 

 and thin outer skin of the bark, and continuing to grow and pufi" out, 

 till in June some inches in length of the limb at the place afiBCted is 

 three or four times its diameter elsewhere. Both the bark and woody 

 fibres are changed into a spongy stthstancc, not at all juicy like the 

 fruit of a tree, of a pale yellow color when growing, but changing to 

 coal-black when it is mature." {Rep. CurcuUo and Black-Knot^ 1860, 

 p. 21.) Although Dr. Fitch states that he " has examined these ex- 

 crescences more closely, perhaps, than has ever been done by any other 

 person," and that he is " prepared to say with the fullest confidence, 



