AMERICAN HOMOPTERA. 283 



well as in the outer stays. The outer stay threads are positively de- 

 monstrative of the structure of the cocoon, even when not seen until 

 after completion. 



Among these Cecidomyian larva) I observed the larva) of two spe- 

 cies of Chalcidida; (probably undescribed) ; subsequently I found the 

 pupfB attached by their abdominal extremity to the leaf; they are of 

 a pale yellow color ; the imago develops a week or two after the Ceci- 

 domijid. 



Mt. Carroll, 111., August 24, 186". 



On a new Genus of APHID.ffi. 



BY IIEXRY SiriMER, A. M., M. D. 



Hamamelistes, nov. gen. 

 Anterior wing with two discoidal veins, the first one branched, the 

 second simple. Posterior wing with one simple discoi- 

 dal vein. Wings laid flat on the back in repose, ex- 

 tending much beyond the body. Body short. Honey- 

 A_^ tubes small or obsolete. Antenna) short, three to five- 

 jointed. 



Hamamelistes cornu, n. sp.* 



Imogo. Usually entirely black, abdomen sometimes brownish, espe- 

 cially beneath. Honey-tubes obsolete or not visible. Wings hyaline. 

 Anterior wing rounded at the apex, first vein forked near the middle, 

 bearing a long branch about parallel with the second vein ; second vein 

 aborted at its origin ; stigma not very conspicuous, being a faint shade 

 darker than the pale dusky intercostal space ; costal vein heavy until 



* Since the description of this species was in type. I observe, from the Pro- 

 ceedrnga of the Entomological Society, Vol. I, p. 305, that in the N. Y. Cat. 

 Homojp. Dr. Fitch has an Aphis, found in conical follicles on the upper surface 

 of the Witch-hazel leaves, which he names Byrsocri/pta hamavieUdis. I have 

 not been able to see a description of his insect, and it is not impossible that my 

 cornu may be synonymous with his hamamelidis ; but it appears improbable, as 

 his species is placed under Bj/rsocrypta — a genus in which the front wing has 

 three simple discoidals and the hind wing two discoidals, and the antennse six- 

 jointed, all of which characters do not accord with my insect. It appears to me 

 that his insect, if it has a distinct existence, must accord with the characters 

 he thus gives it, and the bare fact that it, like mine, inhabits a conical follicle 

 on the upper side of the Witch-hazel leaf, is not, if I understand the rules of 

 science, sufficient to induce me to withhold my description until perchance I 

 iiiisht see his. 



