254 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 1 



Apical process of ninth sternite single 

 and wide, fig. 867. . .longicornis, p. 255 

 3. Color shining blue-black. Lateral lobes 

 of ninth sternite not narrowed at ex- 



867A 



LONGICORNIS 



867B 



Figs. 866-867. — Mystacides, male genitalia. 

 A, lateral aspect; B, tongue of ninth sternite. 



868 



SEPULCHRALIS 



869 



LONGICORNIS 



Figs. 868-869. — Mystacides, female genitalia. 



treme base, fig. 868 



sepulchralis, p. 254 



Color dull gray-black or brownish- 

 black. Lateral lobes of ninth sternite 

 markedly narrow at extreme base, 

 fig. 869 longicornis, p. 255 



Mystacides sepulchralis (Walker) 



Leptocerus sepulchralis Walker (1852, p. 70); 

 cf , 9. 



Larva. — Fig. 865. Length 10 mm. 

 Ground color of head straw color with a 

 pair of dark brown longitudinal lines (some- 

 times broken into spots) fading at the pos- 

 terior margin, and with numerous small 

 brown dots over most of the head area; 

 pronotum ranging from entirely dark brown 

 with a narrow mesal light area to brownish 

 yellow with lateral irregular brown spots; 

 legs straw color wtih narrow dark bands. 



Adults. — Fig. 870. Length 9 mm. Color 

 blue-black, the wings and thorax with an 

 iridescent metallic sheen. Male genitalia, 

 fig. 866, with apical process of ninth sternite 

 divided at base into a pair of slender long 

 processes; claspers short and stocky; tenth 

 tergite subdivided into a group of intricate 

 sinuate blades. Female genitalia as in fig. 

 868. 



In our collecting we have found this 

 species in Illinois only in the glacial lakes 

 of the northeastern part. Betten (1934, 

 p. 281) recorded the species both from this 

 locality and from Charleston, Illinois. In 

 other states, we have found, the species 

 occurs in both lakes and streams; so it may 

 do this in Illinois also. 



We have found the larvae under and 

 around stones in Channel Lake, near An- 

 tioch, and reared them from this locality. 

 Adult emergence occurs from May into 

 September; our records from Illinois are 

 few, but abundant records from other states 

 indicate this long seasonal range. 



This species occurs through the North- 

 east, south to Georgia, and southwest 

 through the Ozarks. Records are available 

 from Arkansas, Georgia, Indiana, Illinois, 

 Maine, Michigan, Minnesota, New Bruns- 

 wick, New Hampshire, New York, Nova 

 Scotia, Ohio, Ontario, Pennsylvania, Que- 

 bec, Saskatchewan and Wisconsin. 



Illinois Records. — Antioch : July 8, 

 1932, H. H. Ross, 3 5, 1 $ . Channel 

 Lake: May 27, 1936, H." H. Ross, 9$, 

 9? ; May 18, 1938, Ross & Burks, \$, \ 



