NO. 10 MORPHOLOGY OF GNATHOTRICHUS SCHEDL 75 



and a few papillae. The galea is largely fused with the lacinia. Dis- 

 tally a rather shallow fold indicates the separation of these two 

 sclerites. 



The setae of the maxillae have not been studied thoroughly enough 

 to decide if they are of taxonomic importance or not. In Den- 

 doctonus valons, no setae or punctures occur on the palpus and none 

 of them on the lacinia, according to the drawings published by Hop- 

 kins. On the other hand it was found that the setal arrangement of 



Table I. — Setae of the head, nomenclature. 



Nomenclature of Dr. Russo Used on New nomenclature Used on 



.Seto 

 .Seto 

 Seto 

 Seto 

 Seto 

 Seto 

 Seto 

 Seto 

 Seto 



Seto 

 Seto 

 Seto 

 Seto 

 Seto 

 Seto: 

 Seto 

 Seto: 



Seto 

 Seto 

 Seto 

 Seto 

 Seto 

 Seto: 



Seto 

 Seto 

 Seto 



Seto 



Seto 

 Seto 



e mediane-distale . . . 



submediane f-Frons Seta fronto-lateralis Frons. 



lateral! 



hasali Frons-epistoma . Seta epistomalis Epistoma. 



basali clypeali Clypeus Seta clypei Clypeus. 



mediane distali "j 



premediane iLabrum Seta labralis Labrum. 



e sublaterali [ 



e basali-laterali J 



Seta verto-mediana ' w t 



Seta verto-lateralis S veiiex. 



e laterale del vertice..'] 



e mediane LCenae Seta geno-lateralis Genae. 



e basale .• • • • | 



e interna del verticc.J 



e della gena "| 



e mediane L Genae Seta geno-mediana Genae. 



e esterna f 



e basale Seta epicrano-lateralis Epicranium. 



e dorsali ll'^'^^u,^ 1^1* mandibulae dorsalis . . . I Mandible. 



a <;nblatprqle basale Mandible Seta mandibulae lateralis., i _ 



a la"ertneTlo Spit^:^ Seta stipitae maxillaris Stipes. 



e mediane del palpifero. [ Palpifer Seta palpiferae maxillaris Palpifer. 



e laterale del palpifero. ''First joint of Seta palpo-maxillaris 1° First joint of 



e palpiale palpus. _ palpus. 



Seta lacinio-maxillaris Laciniae. 



mediane LSubmentum . . . Seta submento-lateralis Submentum. 



subbasali 



Seta menti Mentuni. 



subbasali . . . . l^entum Seta labio palpiferis Palpifer of 



labium. 

 rSefa ligulae distalis. 



"'Stale I Ligula < .Seta ligulae mediana. 



mediane ( j^Scta ligulae basalis. 



Gn. materiarius Fitch is exactly the same as that of CJiactoptdius 

 vestitus Fuchs, illustrated and described by Russo. 



Labium. — The labium (Lab) of the larva is very different in struc- 

 ture from that of the adult. Indications are that the labium of the 

 larva as well as that of the adult will become more and more im- 

 portant as the bearer of taxonomic characters in the Scolytidac. 



The submentum (SM) is present as a large sclerite and is trapezoid 

 in outline. The shape is more like that of Chactoptelins vestitus Fuchs. 

 It is slightly chitinized, laterally connected with the maxillae and 

 bears three pairs of setae (d), the same number and in a similar ar- 

 rangement as in Chaetoptelius vestitus and Dendroctonus valens. 

 Russo called these setae setole subbasale, setole mediane and setole 

 distale in order proceeding distad. The anterior margin of the sub- 

 6 



