'-^- ^'EW YORK STATE MUSEUM 



and the ImiiHM-i yellowish. AbdonuMi blackisl, or bnwiiisl, vontor 

 souietin.os yollowisli. Wiiio-s darker than those of the male the 

 anterior >eius dark, R,^, sliohtl.v l„nved toward the costa bevond 

 Its middle. Jn other respects like the male. Lenuth male' and 

 ItMnale, 2.5 to 3 mm. 



In immature specimens the le-s and i.articniarlv the femora 

 aiv pale. The paler female specimens resend)le i> n"b i t a r s i s • 

 the male differs in liavin- n.. pale mar-ins on the posterior ab- 

 dominal se<»-ments. 



Xnmerous specimens, Tthaca X. Y. Dou.jjlass, Alaska. 

 18. Orthocladius basalis St aejivr 

 1845 C h i r o 11 o m u s Slaesor. KiT.jer : Naturh. Tids. ii. s. 1 : 351. 6 

 1872 C h i r o n o in ii s Holingr. Ofv. K. Vet. Alvad. Forli. 29 • 105 ' 

 1878 C h i r o 11 o m \i s Ost. Sack. Caf 1. Dipf. N. A. p.20. 

 181)8 C b i r o 11 o m 11 s Lundb. Videusli. :^Ieddel. p.270, "co 

 1902 Orthocladius Kertesz. Cat'l. Dipt. 1 : 21G 

 18G9 C b i r o n o m u s p a v i d u s Holmgr. K. Svonsk. Vet. Akad. Handl. 

 8:5, 42 



The followiiiii- is HoImoTen's desciipt ion of p a v i d u s: 

 Male. Antennae a little shorter than the thorax, with fuscous 

 J>lack hairs; the joints somewhat sej.arated. Thorax smooth and 

 wholly shiiuno-, exceptino- the seutellum and metanotum; meso- 

 thorax with thiw stripes, the middle one prodm-ed anteriorly and 

 depressed posteriorly in front of the seutellum, Ayith three short 

 projectmo- ]M)ints: seutellum obtuse, eleyated and pilose. Ab- 

 domen black, subojuuiue, pale haired, the first seo'ment Avholly the 

 l)osterior maroins of the others sliinini?. Wino-s narrow, cinereous 

 white or slio-htly smoky, darker alono- the costa: crossyein 

 straight : subcosta slio-htly curyed, extendino- to about the middle 

 of the wiiio-, with two distinctly spurious veins (folds?) ; fork of 

 the cubitus but little distad of the crossvein. Halteres white or 

 yellmvish. Legs black fuscous, the middle of tibiae or before the 

 base very freipiently j^aler; the middle and hind legs sparsely 

 haired: the fore tibiae and tarsi very short haired:' fore meta- 

 tarsus al)out one third sh,n-ter than the lil)ia. Length 8 mm. 

 Staeger's description of basalis is as follows : 

 Female. Head black, front shining. Thorax with humeri and 

 I)leura in front of base of wings yellowish, the dorsum with thrcv 

 conrtuent black stripes; the sternum gravish black. The coxae 

 shining black. Abdomen velvet black, the first two segments 

 yellowish brown (in fresh specimens perhaips pure vellow) and 

 the posterior margins of the following segments sliining black 

 The wings are somewhat darkened: tiie anterior veins and the 

 crossveins are dark brown and prominent, the other veins are 



