PROC. ENT. SOC. WASH., VOL. 20, NO. 3, MA.K., l!)ls 45 



being the anteriormost prothoracic sternitcs in both instances. 

 If we were to accept Comstock and Kochi's interpretation of the 

 "sternellum," this designation would therefore be applied to the 

 first or second prothoracic sternite (i.e., is or ps of fig. 14) or to 

 the first abdominal sternum. 



In their "Elements of Insect Anatomy" (fourth edition, pages 

 22-24) Comstock and Kellogg, 1902, employ yet another usage 

 of the term sternellum. Thus, the narrow, transverse, anterior, 

 marginal region of the mesosternum, which is a mesothoradn 

 sclerite, they designate as the prothoracic "sternellum" mMelaco- 

 plusfemur-rubrum. They also refer to the mesosternal and meta- 

 sternal lobes of this insect as the sternella of the meso- and meta- 

 thorax. If we accept this usage 6f the term sternellum, it would 

 therefore refer to the anterior transverse marginal region of the 

 mesosternum and also to the mesosternal or metasternal lobes. 



I have been unable to find any other usage of the term sternel- 

 lum by Comstock, but Voss, 1904, evidently believes that Com- 

 stock employed yet another application of the term sternellum, 

 since, in his list of abbreviations on page 756, Voss refers to the 

 hindermost sternite, or spinasternum (i.e., sternite ss of fig. 14, 

 which bears the label "est" in Voss' list on page 756) as the 

 "epimerales sternit, sternellum Comstock." Forbes, 1910, also 

 thinks that the sternite which I have interpreted as the spin- 

 asternum in the Lepidoptera larva (fig. 8, ss) should be called 

 the "sternellum;" so that if we accept these usages, the term 

 sternellum would be restricted to the spinasternum, or hinder- 

 most sternite ss of fig. 14. 



Hopkins, 1909 (page 24), adopts McLeay's terms praesternum, 

 sternum and sternellum, but the term "poststernellum," which he 

 attributes to McLeay, 1830, was introduced by Comstock, 1902, not 

 by McLeay (who proposed the term poststernum instead of post- 

 sternellum, for the sternum of the imaginary fourth sub-segment). 

 In Dendroctonus, only two of the original sternites are represented 

 by chitinized areas, namely the basisternum and the furcasternum 

 (fig. 14, 6s and/s). These are very closely united, and in them 

 certain ill-defined regions have become marked off by the forma- 

 tion of new lines and ridges and other superficial markings which 

 have no especial phylogenetic significance. In his figures 17 

 and 18 of the prothorax and mesothorax of Dendroctonus, Hop- 

 kins designates these purely secondary subdivisions of the basi- 

 sternum and furcasternum as the pivstcrnum, "sternum," 

 sternellum and poststernellum (or areas representing these sub- 

 divisions). If Hopkins' interpretation of the terms presternum, 

 "sternum," sternellum, and poststernellum were adopted, they 

 would therefore' be applied to the secondary subdivisions of 



