\ 



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). 



OrtJiocladius, pt. 



Cricotopus. 



11. All labial teeth rounded or all acute CMronomus, 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 CMronomus. 



— 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 



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 Tlialassomyia. 



— 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 Metriocnemus, pt. 



— 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 i Orthocladtus, pt. 



( .Cricotopus. 



