500 



PSEUDOCHIRONOMUS, n. gen. 



The only species of this genus may be distinguished from Chiron- 

 omus by the short basal joint of the fore tarsi — the length of which is 

 distinctly less than that of the fore tibiae — the distinct apical spur of 

 the hind tibise, and, except in the case of one or two rather aberrant 

 species of that genus, by the shorter third vein, which ends distinctly 

 farther in front of the wing-apex than the fourth vein does behind it. 

 In most respects the genus more closely resembles the members of the 

 old genus Orthocladius in the wide sense, but the hypopygium has a 

 much closer affinity with hypopygia of Cliirouoimis than with those of 

 Orthocladius, the apical portion of the lateral arm being straight — not 

 recurved — and without an apical thorn (PI. XXXVII, Fig. i6). It is 

 more difficult to separate the female from the species of the subgenus 

 Psectrocladius, to which its large pulvilli, and distinct, fringed em- 

 podia would relegate it; but it is more robust, the pronotum has a deep 

 and broad median incision, the post-humeral area has a circular shin- 

 ing depression, and the fore tibia is not conspicuously longer than the 

 basal joint of the fore tarsi. 



I have obtained what I believe to be the pupa of the species, which 

 is described herewith. 



Type of genus, Pscitdochirotionius richardsoiii, n. sp. 



PSEUDOCHIRONOMUS RICHARDSONI, U. Sp. 



Larva. — Unknown. 



Pupa. — Length, 6-8 mm. Brown. Frontal tubercles small, acute 

 apically. Thorax with small closely placed, apically rounded squam- 

 ules; thoracic respiratory organs broken in specimens before me. First 

 abdominal segment with.out setulas ; disc of segments 2-6 covered with 

 distinct setulae, a conspicuous and rather broad band of these setulae 

 near bases of segments 2 to 4, that on the latter composed of weaker 

 setulae than those on the other two segments, the setulse becoming 

 much weaker and being very closely placed as they recede from base ; 

 segments 5 and 6 without distinct band, but with a large rounded 

 patch of setulse which are much longer, though but slightly darker, and 

 are much more closely placed than those on the remainder of disc ; sec- 

 ond segment with the usual transverse apical row of setulae ; segments 

 3 and 4 with a narrow, transverse band of setulae near posterior 

 margin, separated from the setulae on disc by a bare strip ; apical lateral 

 angle of eighth segment with an irregular comb of short thorns ; lateral 

 margins of segments with a few long flattened hairs, fringe of apical 

 appendages confined to apical half, regular in length, and consisting of 

 manv flattened hairs. 



