4— 



that is Pleurostict. On the other hand I assert that the stigmata are all 

 en the connecting membrane and therefore Laparostict. To arrive at 

 this determination with absolute certainty, I have removed the abdomen, 

 divided it into two parts longitudinally ; after having removed the entire 

 contents of the abdomen the segments have been spread upon a piece of 

 glass, permitting one to see the structure absolutely. 



The larva described by Osten-Sacken as that of Pleocoma had been 

 looked upon as very doubtful by me and I so expressed myself to Dr. 

 Leconte. On reading the almost exhaustive arguments of Gerstaecker 

 against its being the true larva I became convinced that the larva is 

 really the larva of Pleocoma. '"It is," says Gerstaecker, "an undoubted 

 Laparostict larva " and there is no other Lamellicorn of that series in 

 California requiring so large a larva. 



Gerstaecker's mistake regarding the stigmata of the imago probably 

 arose from the fact that the upper inflexed portions of the ventral plates 

 are translucent and permit the stigmata to be indistinctly seen through 

 their walls and thus appear Pleurostict. 



The systematic positions of all the ambiguous genera in our fauna 

 were very carefully discussed by the authors of the second edition of the 

 "Classification," and while some may be still open to discussion, Pleo- 

 coma is not. 



As a result of a study of the species of Pleocoma, the following table 

 has been prepared : 



Third joint of antenna: shorter and narrower than the first, the club with but four 

 long lamellae. 



Seventh joint of antenna? merely transverse, not prolonged in a process ; hairs of 

 underside black Rickseckeri,* Horn. 



Seventh joint prolonged in a process, one-third as long as the following joint ; 



hairs of underside yellow fimbriata, Lee. 



Seventh joint prolonged in a process, two-thirds as long as the following joint. 



hairs beneath yellow . . Behrensii, Lee. 



Third joint of antenna; nearly as long and as stout as the first joint. 

 Thorax regularly convex in front, with at most a slight depression. 



Punctures of thorax fine, not greatly coarser in front, surface not hairy 



conjungens,* Horn. 

 Punctures <>t thorax relatively coarse, very conspicuously coarser, denser and 



deeper in front, the surface with semi-erect hairs hirticollis, Schauf. 



Thorax retuse in front, that is, suddenly declivous, with abroad depression poster- 

 iorly behind a transverse, obtuse ridge ; surface finely punctured, not hairy ; 

 geminate stria; of elytra deep and coarsely punctured. 

 Hind angles of thorax distinct but obtuse ; fourth joint of antennae very little 

 prolonged internally Ulkei,* Horn. 



* These species are for the first lime named. 



