188 NEW YORK STATE MUSEUM 



the wing" margin at or a little below the apex; the cubitus is 

 forked ; the R-M crossvein is at about the mid length of the wing ; 

 the humeral crossvein is sometimes wanting. 



To the above description I may add that 11.^^. is present though 

 usually quite delicate. The male genitalia consist of a dorsal 

 downward curved keel, a pair of elongate lateral lobes, a pair of 

 inferior and a pair of superior lobes (pl.32, fig. 7 to 13). 



KEY TO SPECIES OF CHIRONOMUS 



Larvae 

 The tooth on the middle line of a labium having an odd number of teeth 

 will be called the middle or median tooth, the first tooth laterad of this 

 will be called the first lateral ; the second, the second lateral, and so on. 

 "When there is an even number of teeth, the first one laterad of the median 

 line will be called the first lateral ; the second, the second lateral, etc. 

 a Labium with an odd number of teeth (1. e. center line bisects the middle 

 tooth) 

 b Middle tooth broadly truncate, pl.21, fig.lS; i)1.23, fig.15 



c First lateral tooth smaller than the second, second truncate, pi. 23, 



fig.15 59. ? p 1 u m o s u s 



cc First lateral about same size as the third 16. f 1 a v i c i n g u 1 a 



6Z> Middle tooth rounded 

 c Middle tooth trilobed 



d Teeth short, pl.23, fig.S 60. d e c o r u s n. sp. 



(Id Teeth long, pl.23, fig.lS 79. C h i r . sp. 



cc Middle tooth simple 



d First and second lateral teeth rather closely united, pl.21, fig.l 



c Teeth as shown on pl.21, fig.l 25. t e n e 1 1 u s 



ec First and second laterals more distinctly separated than shown 



on this plate 48. dux n..sp. 



dd First and second laterals as distinctly separated as the other 

 teeth 

 c Middle tooth shorter than the first laterals ; blood red larva 



80. Ohir. sp. 

 ee Middle tooth as long or longer lluui the laterals 



f Second and third laterals longer than the first laterals and 



closely united, pl.37, fig.27 63a. t e n t a n » 



ff Not as above 



g Second laterals longer than the first and third 



h As shown on pl.23, fig.l 60a. d o r s a 1 i » 



hh As shown on pl.37, fig.25 63. p r a s i n u s 



gg Teeth gradually becoming smaller from the median line 

 towards the lateral margin 

 h Teeth almost uniform in size, pl.22, fig.7. .81. C h i r . sp. 

 hh Middle tooth distinctly larger 



i Middle tooth semicircular, pl.23, fig.S. .52. 1 o b i f e r u s 

 n Middle tooth hyperbolic, pl.22, fig.ll. .43. modestus- 



