2 GEO. H. HORN, M. D. 



Tlirouo'h the liberality of friendi*, whose kindness will be acknowl- 

 edged in their jtrojier places, sufficient material has been obtained to 

 ])ermit of all necessary dissection, so that the details of Pleocoma 

 will be more thoroughly given than heretofore. At the same time 

 drawings have been prepared to illustrate the parts and to enforce 

 the argument which will follow. 



In the following pages I propose to begin with the generic details 

 and to continue with sufficient descriptions of the species, after which 

 the " Literature" will review- Pleocoma from its beginning to the 

 criticism by Dr. Gerstaecker in the " Stettin Zeitung" for 1883. 



PLEOCOMA Lee. 



Form broadly oval and convex, dorsum slightly depressed, body 

 beneath and legs clothed with moderately long reddish-yellow hair, 

 in one species black, upper surface without hair, the margins fim- 

 briate. Under wings well develo})ed. 



Head relatively small, rather dee})ly inserted, eyes large, globular 

 and prominent ; vertex with a short erect horn obtuse or slightly 

 emarginate at tip ; genie prolonged each side partly dividing the eye 

 and forming a more or less acute free angle. 



Clypeus reflexed, forming a rather broad horn more or less emar- 

 ginate and broader at apex. 



Antennae elev^m-jointed, the first joint stout and conical, second 

 globular, but as thick ; club long in the male, composed of a vari- 

 able number of lamellae from four to seven, the first lamellar joint 

 always glabrous, the others opaque, with sensitive surface. 



Labrum broadly oval, placed either perpendicularly to the axis 

 of the body or slightly obliquely, connate with the clypeus, but with 

 the suture well marked. 



Mandibles visible only by dissection, placed close together against 

 the roof of the mouth, doul)tless immovable, when viewed laterally, 

 of triangular form, the base resting against the roof of mouth, the 

 perpendicular against the inner side of cly})eus, outer side ciliate 

 with long hairs. 



Maxill/E small, the inner lobe in the form of a ])late surround- 

 ing the outer lobe, the lattei' a little longer, terminated by an obtusely 

 ccmical process ; surface ciliate within by moderately long hairs. 



Maxillary palpi i-elatively hmg; first joint shoi-t ; second longest; 

 third half as long, conical ; fourth fusiform, nearly as long as the 

 first. 



