The Chonaphini 151 



Leptodesmus placidus: Bollman, 1888:406; 1893:122. Carl 1903:549- 



551, Taf. 17, fig. 18. Williams and Hefner, 1928:110, fig. lib. 

 Leptodesmus borealis Bollman, 1893:183-184. 



Trichomorpha placida: Attems, 1938:119-120, fig. 139. Causey, 1952:9. 

 Chonaphe michigana Chamberlin, 1946:31-32, figs. 1-2. 

 Semionellus placidus: Chamberlin, 1947:24, fig. 3. Johnson, 1954:248, 



pi. Ill, fig. 19. Chamberlin and Hoffman, 1958:47-48. Kevan, 



1983:2968. 

 Semionellus michiganus: Chamberlin, 1948:258. 



Type specimen — Lost. The type locality is Michigan without further 

 specification (Wood 1864, 1865). 



Diagnosis — With the characters of the genus. 



Color in life — Paranota red, metaterga black with concolorous 

 red bands along the caudal margins. 



Male from Midland County, Michigan (Holotype ofC. michigana) — 

 Length 28.3 mm, maximum width 4.8 mm, W/L ratio 16.7%, D/W 

 ratio 77.1%. 



Head capsule smooth, polished; epicranial suture distinct, terminating 

 in interantennal region. Antennae appearing relatively short and broad, 

 reaching back to caudal margin of 3rd tergite; relative lengths of 

 antennomeres 2>3>6>4=5>1>7. Genae not margined laterally, with 

 distinct central impressions, ends broadly rounded and extending slightly 

 beyond adjacent cranial margins. Facial setae as follows: epicranial 

 2-2, interantennal, frontal, and genal not detected, clypeal about 10- 

 10, labral about 14-14. 



Collum moderately broad, ends not extending below those of 

 succeeding tergite. Paranota well developed on anteriormost segments, 

 becoming noticeably shorter on segment 9 and progressively shorter 

 caudad, moderately declined, angling ventrolaterad and continuing 

 slope of dorsum, anterior corners rounded, caudolateral corners blunt 

 through segment 9, rounded thereafter. Peritremata broad, distinct, 

 strongly elevated above apranotal surface; ozopores located caudal to 

 midlength, opening sublaterad. 



Sides of metazonites generally smooth, polished, with variably 

 curved, shallow impressions. Strictures distinct. Gonapophyses moderately 

 long and stout, extending moderately from 2nd coxa. Pregonopodal 

 sterna glabrous, variably modified; 4th sternum with two long, diverging 

 projections extending ventrolaterad and overlying 3rd coxa (Fig. 27); 

 5th sternum with two short, subconical, paramedian knobs between 

 4th legs, flat between 5th legs; 6th sternum strongly depressed to 

 accommodate telopodites. Postgonopodal sterna glabrous, with bicruciform 

 impressions, caudal margins gently curved, without modifications. 



