ADDENDA 



A number of larvae representing- three species were taken by 

 Mr. R. E. Richardson from the stomach of a shovel-nose sturgeon. 

 The fish was caught June 1904 in the Mississippi river -near 

 Grafton, Illinois. All the specimens were in rather poor con- 

 dition, but they nevertheless exhibit peculiar characters which 

 prevent placing them in any of the foregoing genera. Two of 

 them (A and B) are certainly members of the group Chironomus, 

 and possibly belong to the genus Tanytarsus. The third one is a 

 Chironomid having both Chironomus and Ceratopogon affinities. 



Chironomus sp. A. 



Length 7 mm. Body stout, greenish in color; head brown, small, 

 only about half as wide as the thoracic segment, tapering; eyes 

 each consisting of two small distinctly separated pigment spots, 



Fig. 18 Mandible and labium; larva A x400; larva B x!80 



situated as far cephalad as the margin of the labium. Anterior 

 prolegs with rather numerous curved setae; posterior prolegs 

 slender with a few bilobed pale brown claws. Antennae long, 

 more than half the length of the head, three- jointed, besides the 

 short basal prominence and two slender apical processes; first 

 joint long, second very short, no longer than wide, third about f 

 as long as the first. Mandible stout, darkened apically, with 

 moderately stout teeth; labium with margin concave (see figure). 

 Teeth arranged on each <side of the center line, the middle section 

 toothless. There are four anal blood gills but there are none on 

 the ventral surface of the eleventh segment; above the superior 

 pair of anal -gills are two stout setae; the dorso-caudal papillae 

 are short, each with a tuft of long pale brown setae. 



