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Siiperfamil}^ CuUcoidea 



This supcrfamily includes the following families according to the 

 present arrangement : Psychodidae, Blepharoceridae, Culicidae, and 

 Dixidae. The last family has been considered by some writers as a 

 subfamily of Culicidae. There are, however, very marked differences 

 between the corresponding stages of Culicidae and Dixidae which I 

 believe warrant their recognition as distinct families. 



SUPERFAMII^Y CHARACTERS 



Ibarra. — All the larvae of the group make primary or exclusive 

 use of the anal spiracular appendages for respiration, Culicidae mak- 

 ing exclusive use of them except in a very few cases. The larvae of 

 this family are distinguished from those of any allied family by the 

 fusion and very noticeable expansion of the thoracic segments. Many 

 larvae of the subfamily Corethrinae (Culicidae) are remarkably 

 specialized in having air-sacs in the thorax and near apex of abdomen. 

 which show as blackish spots, and are without the elongate anal re- 

 spiratory tubes of the normal forms of the Culicinae. These larvae 

 are sometimes found at great depth in lakes, under anaerobic con- 

 ditions. The larvae of Blepharoceridae have the thoracic and first 

 and second abdominal segments fused and the head poorly differ- 

 entiated. The lateral abdominal spiracles in this family are not func- 

 tional. Some Psychodidae have larvae that superficially resemble 

 those of Blepharoceridae in general form, even having median 

 ventral sucker-like discs on abdomen as that family has; but the 

 thoracic segments are not so closely fused, the head is well differ- 

 entiated, and the apical segment has a more or less elongated respira- 

 tory tube instead of its being rounded. The larvae of Dixidae in 

 general appearance resemble those of Chironomidae, but they differ 

 from the latter in having pseudopod-like protuberances on dorsum of 

 basal two abdominal segments, and the head differs greatly from that 

 of Chironomidae. These characters, in my opinion, taken in conjunc- 

 tion with those of the wing of the adult, associate this family more 

 closely with the Culicidae than with the Chironomidae. 



Pupa. — The thoracic respiratory organs are elongated in all fami- 

 lies of Culicoidea. The pupae of Culicidae and Dixidae have the legs 

 recurved against the ventral surface of the base of the abdomen so 

 that they scarcelv protrude beyond the apices of the wings. The legs 

 in Psychodidae and Blepharoceridae are straight, but do not extend 

 beyond apices of wings, or, at most, but slightly beyond. For other 



