] 



289 



10. Maxillary palpi usually noticeably longer than their diameter; an- 



terior margin of labium transverse or slightly convex, the sides 

 not sloping abruptly away from the central portion (PI. XLIII, 

 Fig. 4) 11 



— Maxillary palpi usually about as long as their diameter; anterior 



margin of labium usually centrally transverse, the sides sloping 

 abruptly backward from the central portion (PI. XLIII, Fig. 2). 



Ortliocladius, pt. 



Cricotopus. 



11. All labial teeth rounded or all acute Cliironomus, pt. 



— Central labial tooth rounded, broader than laterals, which are very 



acute Diamesa. 



PUPAE 



1. Thoracic respiratory organs consisting of numerous long hair-like 



filaments Cliironomus. 



— Thoracic respiratoiy organs stalk-like, sometimes furnished with a 



few surface filaments ; or sessile 2 



2. Abdominal segments in part with paired spot-like groups of con- 



spicuous black spinules which are visible to the naked eye 



Tanytarsus. 



— Abdominal segments without distinct spot-like groups of black spin- 



ules, the surface either bare or with much less conspicuous arma- 

 ture which is distributed over a large area of each segment and 

 is only visible under a strong lens 3 



3. Thoracic respiratory organs sessile 4 



— Thoracic respiratory organs stalk-like 7 



4. Abdominal segments without stout teeth on their posterior margins, 



and otherwise unarmed Camptocladius. 



— Abdominal segments, except basal and apical, with stout teeth on 



their posterior margins, or with setae on dorsum 5 



5. Setulae confined to disc of segments, no postmarginal teeth or spines 



present TJialassomyia. 



— Short teeth or spines present on posterior margins of some of the 



abdominal segments 6 



6. Disc of dorsal segments with a band of distinct setulae ; apical ap- 



pendages without long hairs Metriocnemns, pt. 



— Disc of dorsal segments without a band of distinct setulae ; apical 



appendages each with 3 long hairs Diamesa. 



1. Abdominal segments, except basal and apical, each with a con- 

 spicuous postmarginal series of strong spinules 8 



— Abdominal segments, except second, without a conspicuous post- 



marginal series of strong spinules J Ortliocladius, pt. 



j .Cricotopus. 



