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 (PL XLIII, 

 Fig. 4) -H 



— jMaxillary 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). 



J Orlliocladius, pt. 



j Cricoiopus. 



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



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



acute Diamesa. 



pupap: 



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



maments Cliironomus. 



Thoracic respiratory 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 



TanytarsiLS. 



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 Tlialassomyia. 



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



abdominal segments • *5 



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



pendages without long hairs 3Ietnoc7mnus,j)t. 



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



appendages each with 3 long hairs .Diamesa. 



7. 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 Ortlwcladius, pt. 



I .Cricofopus. 



