21 



pupa-cell above the water line and changes in the bottom of the same, with the head 

 upwards. It Jeaves the epidermis, closing the place of exit, and the freed moth breaks 

 through this with its clypeal spine when it escapes, leaving the pupa skin in the cell. 

 The elongate pupa has a very stout, blunt clypeal spine. The moth appears in August. 

 It is known to abCTund throughout western New York, central Michigan, and eastern 

 Wisconsin. 



Third. — The larva of a Ghilo {V) bores the stems of Scirpus. Its habits are similar 

 to those of a Nonagrian. It passes the winter in the old stems, and after the new ones 

 appear it bores into them, passes below the water line, and lives low down in the stem. 

 It is mature late in June, when it forms a pupa cell with its place of exit above the 

 water. The pupa breaks up the epidermis left by the larva, covering the place of escape, 

 but does not force its way out before disclosing the moth, in a manner similar to that of 

 the -^gerians and others. It is enabled to do this by means of clasps on the abdominal 

 rings, and the sharp or pointed clypeus. 



Mr. Riley, in commenting on Dr. Kellicott's communication, said that he had been 

 greatly interested in the facts presented, and especially as to the pupation of the Nona- 

 gria. As to the difference in the clypeal projection in the two pupae exhibited, he 

 thought it might be sexual, as in all cases where the clypeus was produced sexual differ- 

 ence occurred, the greatest development being, so far as he had observed^ not in the male 

 but in the female. He had recently called attention in the Naturalist to the correllation 

 between the produced clypeus and the horny, exsertile ovipositor, and the fact that they 

 indicated endophytous larval habit. The various methods of imaginal exit in stem-boring 

 iepidoptera, and the structural modifications that resulted, were most interesting to the 

 philosophical entomologist. In some species, as in the Nonagrian here mentioned, the 

 clypeal point on the pupa seemed merely a consequence of the necessary point in the 

 imago, the pupa remaining in its burrow and the imago boring out. In others, as in 

 Prodoxus decipienSj the similar clypeal point on the pupa permitted it to partly bore out 

 of the stem and thus release the imago, which had no homologous point, but an unarmed 

 head. In some borers the larva prepared a little door which the imago easily pushed 

 open, the pupa remaining inactive within its prison ; while in others, closely related, the 

 pupa did the work by forcing itself partly out. There could be no question of the 

 digoneutic nature of Arsame ohliquata at Washington, and none as to its variability as 

 illustrated by his specimens, vulnijtca and melanopyga, being doubtless but forms of it. 



Some specimens of Cantharis Nuttali were exhibited by Prof. Hiley, it being stated 

 that in Dakota they were accused of devouring the growing wheat. 



The meeting then adjourned, when the members spent some time in informal con- 

 versation, and in examining the microscopic specimens illustrating Prof. Osborn's paper. 



\ 



3 [en.] 



