375 



Length: male, 2.5 mm.; female, 2 mm. 



Type locality, Dubois, 111., April 24, 1914; swept from vegetation 

 in creek valley (C. A. Hart and J. R. Malloch). 



A male taken at Palo Alto, California, May i, 1906, submitted by 

 Professor Aldrich, may belong to this species, but its condition is too 

 poor to permit a definite opinion. 



This is in all probability the same species as that itlentified by Pro- 

 fessor Johannsen as T. indecisiis Williston. The latter was described 

 from St. Vincent, West Indies, and apart from the unlikelihood of its 

 occurring so far north as New York and Illinois there are sufficient 

 differences between the two descriptions to warrant their separation as 

 distinct species. 



7. Tanypus moniIvIS Linne 



lipnla Dwnilis Linne, Syst. Nat. X, 1758, p. 587. 



Larva. — (PI. XXIV, Fig. i). Length, 6 mm. Brownish or yel- 

 lowish in color. Head brownish yellow, nearly twice as long as wide ; 

 antennae very long and slender (PI. XXIV, Fig. 2) ; maxillary palpi as 

 in Figure 10; mandibles with apical half slender, towards the extrem- 

 ity distinctly blackened ; labium with five teeth, its apex conspicuously 

 blackened (PI. XXV, Fig. 7) ; lateral labial process with two branches. 

 Anterior pseudopods with curved claws; no hairs on abdominal seg- 

 ments ; anal pseudopods slender and very much elongated, their apices 

 armed with curved claws arranged in two circles, and consisting of 

 numerous slender pale claws with several shorter and stouter black 

 ones. Dorsal sensory tufts consisting of six hairs, situated upon bases 

 which are about six times as long as their own diameter ; four dorsal 

 respiratory organs present and above them two weak hairs. 



Pupa. — Length, 4.5 mm. Dark yellowish or, when nearing ma- 

 turity, brownish. Thoracic respiratory organs black or brownish, 

 shape as in Figure 19, Plate XXIV. A transverse row of short thorn- 

 like tubercles near base of respiratory organ. Apical appendages of 

 abdomen sharply pointed, and with very few margmal hairs. 



Imago; Male and Female. — Yellowish brown to dark brown. Head 

 yellowish or brownish ; antennae yellow, basal joint brown, the plumes 

 brown; palpi yellow. Mesonotum generally distinctly vittate and 

 grayish pollinose on the spaces between the vitt^e; scutellum yellow; 

 postnotum brown on disc. Abdomen generally translucent yellow 

 with the bases of the segments more or less suffused with brown and 

 the apical segments entirely brownish. Legs whitish yellow, with 

 brown rings as follows : near apex of femora, near base of tibiae, 

 beyond middle and at apex of same, before middle and at apex of 



