213 



Keys to Genera 



larvae 



1. Apical abdominal segment appearing cleft, the margins of the 

 cleavage fringed with hairs ; body with close pubescence ; apical 

 ventral blood-gills slender, pointed Dicranomyia simulans. 



— Apical abdominal segment rounded or slightly truncate, not cleft, 



and without hairs ; body not pubescent ; apical ventral blood-gills 

 stout, rounded Limnobia. 



PUPAE 



1. Thoracic respiratory organs broad, subquadrate, their apices trun- 

 cate, the bases with a hook-like protuberance 



Dicranomyia simulans. 



— Thoracic respiratory organs rounded, ear-like, without any hook- 



like protuberances at base Limnobia. 



Dicranomyia simulans Walker 



"Limnobia simulans Walker, List of Diptera in British Museum Coll., Pt. I 



(1848), p. 45. Imago. 

 Dicranomyia simulans ("Walker) Needham, 23d Eep. State Ent. N. Y., p. 214. 



(1907) 



Larva. — Length, n-13 mm. Green, with distinct fuscous marks 

 on dorsum which are broken up by small round clear spots and ir- 

 regular clear patches. A close examination discloses the fact that the 

 fuscous areas are composed of closely placed spinose hairs, while the 

 clear spots are either devoid of hairs or yellowish hairs are present. 



Head large, similar in general appearance to that of Limnobia; 

 antennae long, the shaft about 3 times as long as its greatest diameter; 

 maxillary palpi short and inconspicuous ; labium slightly convex in 

 outline, central tooth much longer and stouter than the first lateral, 

 second and third laterals as large as central. Thoracic and abdominal 

 segments each with distinct anterior marginal fusiform area, these 

 areas not armed with distinct spinules ; incisions between dorsal seg- 

 ments of abdomen margined with blackish spinules which are ap- 

 preciably, but not much, stronger than the hairs on the fuscous dorsal 

 markings ; apical segment with a cleft appearance, the aperture clos- 

 ing, mouth-like, with the lips vertical. 



Pupa. — Length, 8-9 mm. More fuscous than the larva. 



Thoracic respiratory organs as in Figure 5, Plate XXXTII. their 

 structure separating them from any other genus known to me. My 

 onlv specimen is in a fragmentary condition, which prevents me from 



