FIELD BOOK OF INSECTS. 



6. Wings almost always hairy, with only a few longitudinal 

 veins (as a rule 3, rarely 5), very often without apparent 



cross-veins. Antennae long and slender 



ITONIDID^E (p. 242). 



Wings always with more than 3 longitudinal veins and, 

 as a rule, with apparent cross-veins. In doubtful cases 

 there are either more than 5 longitudinal veins or else the 

 antennas are rather stout, shorter than the thorax 7. 



7. At least 9 veins reach the margin of the wings, the 

 second and fourth longitudinal veins being forked; costal 

 vein continuing all around the wing 8. 



Less than 9 veins terminate in the margin of the 

 wing; the veins never very hairy or scaly 10. 



8. Veins bare; second longitudinal veins strongly arched 

 forward DIXID^E (p. 236). 



Veins including the hind margin, and also body, very 

 hairy or scaly 9. 



9. Wings ovate or pointed, with numerous longitudinal 

 veins and without apparent cross-veins. Small or minute, 

 moth-like flies; the wings, when at rest, held like a roof 

 above the abdomen PSYCHODID^; (p. 236). 



Wings elongate, narrow, not held roof -like against the 

 body, with the anterior cross-vein near the middle of the 

 wing distinct CULICID/E (p. 238). 



10. Antennae as a rule shorter than the thorax, rather 

 stout, without constrictions between the joints. Body 

 often stout, not mosquito-like n. 



Antennas long and slender, the joints longer than 

 broad. Second basal cell usually open (posterior cross- 

 vein wanting). Body slender, mosquito-like 12. 



11. Second basal cell usually closed by a cross- vein. 

 Often medium sized BIBIONID^: (p. 243). 



Second basal cell open (or wanting). Never more 

 than .25 in. long, with large and broad wings. SIMULIID.E 



(P- 243)- 



12. Coxae, as a rule, much elongate. All the tibiae with 



apical spurs. Ocelli, as a rule, present. MYCETOPHILID/E 



(p. 242). 

 Coxae at most moderately long. Tibiae usually 



without apical spurs. Ocelli absent CHIRONOMID^E 



(p. 241). 



232 



