MAY FLIES AND MIDGES OF NEW VullK 251 



Pupa. The thoracic i-espiratorv orgaus are simjjle, tube-like, 

 sometimes with enlarged extremities. Abdominal segments with 

 minute and short setae. The anal segment with 6 terminal setae, 

 three on each side. 



The larvae and pupae of r t h o c 1 a d i u s do not seem to 

 differ from Cricotopus. 



Imago. This genus resembles C li i r o u o m u s . from which 

 it is distinguishable in having the fore metatarsus a luilf or a third 

 shorter than the tibia. The last abdominal segn:ent of the male 

 is much shorter than the preceding and is broader than long; the 

 claspers are short and broad, and usually white in color (pl.33, 

 fig.2j. The legs are white and black annulate, the fore tai'^i are 

 bare or covered with very short and inconspicuous hair (in an 

 exceptional case the male has bearded tar-si) ; the hind tarsi are 

 also usually bare. The halteres are always white or pale yellow. 

 Wings bare, the anal angle, particularly in the male, is promi- 

 nent; R^_Lj is straight or slightly bent at its extremity, the cross- 

 vein is a little beyond the middle of the wing; the cubitus is 

 forked, the base of the fork a little distad of the crossvein; the 

 lower branch is straight or gently arched toward the hind mar- 

 gin ; the humeral crossvein is wanting or rudimentary. 



The species of this genus are all small (2 to 4 mm.) and with 

 black and yellow coloring, the dorsum of the thorax has 3 shin- 

 ing black stripes, which sometimes are so wide as to entirely 

 obliterate the yellow dividing lines, so that only the humeri remain 

 yellow. 



KEY TO SPECIES OF CRICOTOPUS 



Larvae 



a Sides of each abdominal segment with pencil of long hairs, pl.24, fig.9 



3. trifasciatus 

 aa Abdomen without such pencils 



6 Middle tooth of the labium longer than the first laterals, 1)1.24, 



figs. 1, 2, 4 4. e X i 1 i s n. sp. 



hi) Middle tooth about as long as the first laterals, pi. 2.5, fig.22 



6. T a r i p e s 

 Pupae 

 a Pattern upon each abdominal segment in two wide transverse bands, 



resembling that shown on pl.25, fig.7 4. exilis n. sp. 



aa Not marked in this manner 



h Markings as shown on pl.24, fig.7; thoracic respiratory organs as 



shown on fig.8 3. trifasciata 



&6 Dorsum uniformly covered with minute spines 6. varipes 



