in the Illinois River near where the above described adults were 
obtained. One of these we have bred to meridionale ; the other 
is different from any described species, and may be provisionally 
associated with johannseni. The larva has been taken on sub¬ 
merged willows along the river margin, and also by dredging, and 
is apparently very abundant. The pupa has uniformly only four 
gill filaments—a smaller number than has any other species known 
to me. 
Fig. 6. Simulium johannseni , antenna and mouth-parts of larva: a, labium from beneath, 
ventral view; b, mandible, ventral view; c, toothed tip of mandible; c/, antenna; e, maxilla, 
ventral view. 
The larva (Fig. 5) somewhat resembles that of venustum. 
The alcoholic specimens are rather light-colored, marked with 
fuscous cross-bands and patches. The fans have about forty-eight 
rays. The antennae are hyaling, faintly tinged with yellowish, the 
third joint slightly more than one-third the length of the first. 
The mandibles (Fig. 6, b,) have the apical pair of bristles; the 
apical teeth are castaneous. The maxillary palpus (Fig. 6, e) 
bears a few scattered bristles. The toothed area of the labium 
