2 PROC. ENT. SOC. WASH., VOL. 20, NO. i ; JAN. mis 



THREE HUNDRED AND SIXTH MEETING, OCTOBER 4, 1917. 



A REVISION OF THE DIPTEROUS FAMILY CLUSIODIDAE 



(HETERONEURIDAE) . 



J. R. MALLOCH. 



During the last three years I have collected a large amount of 

 material in this small and interesting family, and finding some 

 new or rare forms and the early stages of one species I consider 

 that a short revision of the whole may be of value to students 

 of Diptera. 



I had purposed including the matter in the present paper in a 

 comprehensive treatise of the Cyclorrhapha, but find that such 

 course is not possible because of the limited facilities for publica- 

 tion that are at present available, and in order to limit the size 

 of my subsequent paper I now present this revision. 



The family name has recently been changed to comply with 

 the rule of priority, Heteroneura, a preoccupied name, having 

 been supplanted by Clusiodes. 



Family Clusiodidae. 



Family Characters. 



Larva. Musciform; the head rudimentary consisting of 2 small yel- 

 lowish downwardly directed projections, and without a chitinized internal 

 skeleton; thoracic segments tapered anteriorly; apical abdominal segment 

 slightly rounded; each spiracle on a raised chitinized bifid plate. 



Puparium. Rather slender; rounded at both extremities; metathoracic 

 spiracles not developed; posterior spiracles as in larva. 



Imago. Head broad, eyes widely separated; orbits with 3 pairs of strong 

 bristles; vibrissae well developed; antennae of moderate size, third joint 

 not much elongated, generally little longer than broad; arista pubescent 

 or densely hairy ; f rons often with a pair of cruciate frontal bristles. Tibiae 

 usually with distinct preapical dorsal bristle. Cross veins of wings closely 

 approximated except in Clusia, 9 auxiliary vein complete; first vein falling 

 much short of wing-middle; basal cells complete; sixth vein not extending 

 to margin of wing. 



Habits of Larvae. 



The larvae live in decaying wood and are very sluggish in habit . 

 Some European species have been recorded as leaping, but I saw 

 no indication of such activity upon the part of the larvae Iliad 



