NO. 10 MORPHOLOGY OF GNATHOTRICHUS — SCHEDL 3 



papers, one on the sensory and secretory organs, the muscle struc- 

 ture, the respiratory, circulatory, and nervous systems of the larva 

 and imago ; the other on the metamorphosis and histological investi- 

 gations. Whether or not a biological study will complete the work 

 depends upon the time at the author's disposal. 



The study comprises only the North-American species Gnatlio- 

 tricJins materiariiis Fitch, sulcatus Lee. and retusus Lee. The neces- 

 sary material, dried and mounted adults of the two western species 

 Gn. sulcatus Lee. and retusus Lee, was kindly provided the Dominion 

 Entomological Branch from the Canadian National Collection in 

 Ottawa. For the adults, pupae and larvae of Gnathotrichus nia- 

 teriarius Fitch, I have to thank Mr. L. J. Simpson, of the Dominion 

 Entomological Laboratory, in Fredericton, N. B. All the necessary 

 slides were prepared by the author. The specimens were dissected 

 under water and the mounts imbedded in euporal. The drawings are all 

 by the author, and were done with the aid of the camera lucida using 

 transmitted light. 



Attempts to obtain larvae and pupae of the western species were 

 unsuccessful and therefore the discussion of the larval and pupal char- 

 acters are based on material of Gn. inateriarius Fitch only. A sup- 

 plement on this account will be published in another paper. 



Abstracts of the Literature up to Date 

 A. THE GENUS 

 1868. ElCHHOFF, W.(3). 

 Original description of the genus: 

 Tarsorum articulis tribus primis simplicibus. Antennarum funicolo 5-articu- 



lato, capitulo distincte triannulato. Ligula parte fulcrali angustior. Palpi 



labiales articulis primo et secundo subeaqualibus, simplicibus, tertio niinimo. 



A'laxillarum mala apice rotundata, setis falcatis densissimis ciliata, pal- 



porum articulo primo majore obconico, secundo minore subquadrato, tertio 



cylindrico elongate. 

 With respect to the position of the genus GnathotricJius in the 



family Scolytidae, Eichhoff states : 

 Die Gattung lehnt sich durch die Form der Arten und dichte Bewimmerung 



der Maxillarlappen auf der einen Seite an die Gattung Xylebonis, auf der 



anderen an Corthylus und Ptcrocyclon an. 



1876. Leconte, J. L., and Horn, H. G. (9). 



Leconte, knowing of the new genus Gnathotrichus Eichh., still 

 places the species of this genus under Pityophthorns Eichh. 

 However, he subdivided the genus into subgroups, the first of 

 which comprised the species of the present genus Gnathotrichus 

 described at his time. 



