370 



3- Tanypus decoloratus, n. sp. 



Larva. — Length, 5 mm. Almost entirely white, only the labial 

 plate, apices of mandibles, and claws of the posterior pseudopods 

 brown. Head about twice as long as its greatest breadth ; sides slightly 

 convergent on apical half ; antennae slightly more than half as long as 

 head, the apical portion about one fifth as long as the basal; basal 

 portion of the maxillary palpus slender, subequal in length to the 

 apical portion of antenna, the apical processes short, barely longer 

 than the diameter of the basal portion; mandible as in Figure i, Plate 

 XXVI; labial plate similar to that of monilis (PI. XXV, Fig. 10). 

 In other respects similar to the larva described as pilosellus ( ?). 



Pupa. — Length, 4 mm. Yellow, the thorax and the anterior half 

 of each abdominal segment shaded with brown. Thoracic respiratory 

 organ as in Figure 6, Plate XXVII ; laterad of respiratory organs, a 

 short transverse row of about twelve minute thorns. Abdominal 

 segments, except the last two, without lateral hairs ; seventh segment 

 with four lanceolate hairs on each side; eighth segment with similar 

 hairs on almost the entire length of lateral margins, a longitudinal 

 row of microscopic hairs midway between the median line and the 

 lateral margin, and a group of stronger hairs at the anterior lateral 

 angle; apical processes similar to those of pilosellus ( ?). 



Imago; Male. — Pale buff. Antennae and their plumes brownish 

 yellow. Thoracic vittse pale reddish brown, postnotum slightly dark- 

 ened on dorsum. Basal half of each abdominal segment brownish on 

 dorsum. Legs pale yellow. Wings clear, the cross vein brown, other 

 veins yellow. All hairs on body and legs yellow. Halteres whitish. 



Antenna distinctly longer than head and thorax together, second 

 joint yellow and much swollen. Mesonotum with long soft hairs on 

 the spaces between vittae and several shorter hairs in front of wing- 

 base. Abdomen slender; segments with rather long hairs; apical 

 lateral recurved process of hypopygium slender, nearly as long as basal 

 portion, its shape very much as in hypopygium of Tanypus monilis 

 (PI. XXVIII, Fig. i). Legs slender, mid and hind pairs, with the 

 exception of the last three tarsal joints, long-haired; fore tibia about 

 one fifth longer than basal joint of fore tarsus; all tarsi with the fifth 

 joint much shorter than the fourth. Cross vein very slightly before 

 the middle of wing; costa extending to curve at apex of wing; media 

 reaching margin a little behind tip of wing, slightly deflected near 

 apex; cubitus forks slightly before cross vein; surface of wings with 

 regularly distributed short hairs. 



