306 



PSYCHE. 



[January iSgg. 



of the mouthparts in all of these families 

 is much alike and not difficult to under- 

 stand. The homologous parts in the 

 mouths of the various Nematocera are 

 readily distinguishable and comparable. 

 These mouthparts as compared with the 

 mouthparts of the specialized Diptera, 

 Musca for example, are distinctly gener- 

 alized. Now if the parts of the specialized 

 dipterous mouth, as that of Musca, can 

 be homologized with the parts of the 

 generalized mouth, as presented by the 

 Nematocera, then the remaining prob- 

 lem is to homologize the mouthparts of 

 the Nematocera with the mouthparts of 

 other insects, with the racial orthopter- 

 ous type of mouthparts. 



In order that the testimony from the 



study of comparative anatomy alone may 

 be sufficient to solve our problem it is 

 necessary that (rtr) there be a series of 

 gradatory mouthpart conditions present 

 among Diptera sufficiently continuous to 

 indicate unmistakably the homologies of 

 the mouthparts within the order, and (b) 

 that the generalized dipterous mouth- 

 parts be sufficiently generalized to admit 

 of a certain comparison and homologiz- 

 ing of the parts with the mouthparts of 

 other insects in whose case the homol- 

 ogies of the mouthparts with those of 

 the racial orthopterous type are authori- 

 tatively accepted. Whether these con- 

 ditions obtain may be, I hope, re- 

 vealed by the final publication of my 

 studies. 



AN UNKNOWN TRACT ON AMERICAN INSECTS BY THOMAS SAY. 



BY SAMUEL H. SCUDDER, CAMBRIDGE, MASS. 



In the library of the Boston Society 

 of Natural History, among the works 

 received from the library of Dr. T. W. 

 Harris, is a tract which seems to have 

 escaped the notice of bibliographers and 

 others. Strangely, it does not even 

 appear in the Catalogue of the Harris 

 Library, (Proc. Bost. soc. nat. hist., vii, 

 266-271), nor is it contained in the 

 " Complete Writings " of Say, edited by 

 LeConte. It is an octavo pamphlet of 

 seventeen printed and numbered (3-19) 

 pages besides the title page, the reverse 

 of which is blank, and describes for the 

 first time twenty-two insects; of these 

 all but two are redescribed in later 



papers in the same terms with scarcely 

 a change. The remaining two, however, 

 are not found at all in the Complete 

 Writings and appear to be quite over- 

 looked by subsequent writers, the Pen- 

 tatoma being unmentioned by Uhler in 

 his Check-list of the Hemiptera Heter- 

 optera of North America (1886), and 

 the Trypeta not being found in Osten 

 Sacken's Catalogue of the described 

 Diptera of North America (1878.) 



The title page of the tract reads as 

 follows : Descriptions of 'new species of 

 North American insects, found in Louis- 

 iana by Joseph Barabino. By Thomas 

 Say. March, 1831. Indiana. Printed 



