FAMILY CHIRONOMID-i: THE MIDGES 73 



15. Third vein fused with the costa and not reaching beyond the apical 



three-fourths of the wing-; a false vein running close to anterior 



margin of wing (9 ) Corynoneura Winnertz 



Third vein free, no false vein 16 



16. Wings with haii's 17 



Wings bare 20 



17. The thick crossvein joining the third and fourth vein very long and 



appearing as the base of the third vein 18 



The crossvein short 19 



18. Mesonotum conically produced in front; wings spotted. .Eurycnemus Wulp 

 Mesonotum not produced; wing unicolored Brillia KiefTer 



19. Pulvilli absent; wing hairs decumbent (13) Metriocnemus Wulp 



Pulvilli present though small; wing hairs suberect (Spaniotoma Ed- 

 wards (10) Orthocladius Wulp 



20. Mesonotum with a longitudinal fissure; wings black with white markings 



in most species Chasmatonotus Loew 



Mesonotum without longitudinal fissure 21 



21. Claws cleft; large marine species (Telmatogeton Coquillett, not 



Schiner) Paraclunio Kieffer 



Claws not cleft 22 



22. Palpi porrect, 3 segmentetl (Symbiocladius) Trissocladius Kieffer 



Palpi flexible, 4 segmented 23 



23. Fourth segment of at least the hind tarsi cordifcrm, shorter than the 



fifth (Thalassomyia Johannsen, not Schiner) Cardiocladius Kieffer 



Fourth tarsal segment linear 24 



24. Dorsocentral hairs minute and decumbent; tibia; usually banded with 



white; genitalia in most cases in part pure white (4). . .Crictopus Wulp 

 Dorsocentral hairs larger and suberect; tibise not banded (Spaniotoma 

 Philippi) Edwards, Psectrocladius, Trichocladius, Dactylocladius, Camp- 

 tocladius) (10) ^Orthocladius Wulp 



25. Wing disc with hairs at least at tip 26 



Wings quite bare, the anterior crossvein distinct and oblique 27 



26. Squamte fringed; anterior crossvein distinct and oblique (1). 



Pentapedikim Kieffer 

 Squamse quite bare, anterior crossvein longitudinal in position or indis- 

 tinct (2) Tany tarsus Wulp 



27. Eyes widely separated, reniform; all tibiae with long conspicuous spurs; 



pronotal collar large; basal segment of anterior tarsus not longer 



than the tibiae Pseudochironomus Malloch 



Eyes with dorsal projection; front tibial spur indistinct or absent; 

 basal segment of anterior tarsus longer than the tibia (5). 



Chironomus Meigen 



The genus Chirocladius Picado, represented by a species from Costa 

 Rica, and which seems to belong among the Chironominge, is too briefly de- 

 scribed to place in the key. 



* Pseudochironomus Malloch, with widely separated reniform eyes and very large pronotal 

 collar, in spite of short basal segment of the anterior tarsi and the tibial spurs, belongs with the 

 next section. 



