OF WASHINGTON. 143 



DIVERSE MOSQUITO LARVAE THAT PRODUCE SIMILAR 



ADULTS. 



By HARRISON G. DYAR and FREDERICK KNAB. 



In going over somewhat carefully the material in Culicid larvas 

 that has been gathered by Dr. Howard to be figured, the writers 

 have met in more than one instance with diverse larvae that pro 

 duced adults so similar that they have not been differentiated 

 with the material now at hand. As examples we cite : 



Culex cantans Meigen. 



1. What we have considered as the normal form has the air 

 tube about three-and-a-half times as long as wide, the pecten con 

 sisting of two rows of teeth with the distal two or three detached. 

 The tracheal tubes are broad, band-shaped, slightly waved seg- 

 mentarily, broadened within the air tube. The long abdominal 

 hairs on segments 3 to 6 are single ; the hairs on the head are in 

 tufts of two or three centrally, five in the tuft next the antennae. 



2. The second form has the air tube about four times as long 

 as wide, the pecten of evenly spaced teeth without any detached. 

 The tracheal tubes are very narrow, uniform, strongly bent seg- 

 mentarily, especially in abdominal segment 7, where they form 

 acute angles, likewise narrow within the air tube. The long ab 

 dominal hairs on segments 3 to 6 are double ; the hairs on the 

 head have three to four hairs in the central tufts, about nine in 

 the tuft next the antennas. 



Both forms have been taken at Springfield, Mass., by Dr. Geo. 

 Dimmock and Mr. F. Knab, in temporary pools in fields and 

 woods formed by the melting of the snow in the spring. 



There must be two species here in spite of the apparent simi 

 larity of the adults. 



Culex restuans Theobald. 



1. The usual form has the air tube about three-and-a-half times 

 as long as wide, slightly fusiform, strongly tapering to the tip, 

 furnished with about six scattered hairs, coarse, single, only the 

 one nearest the tip sometimes in the form of a small tuft. The 

 anal processes may be much elongated. 



2. The other form has the tube about four times as long as 

 wide, slender, not fusiform, gradually tapering, the only hair a 

 small tuft beyond the outer third. Otherwise, as in the usual 

 form, the antennas and the peculiarly shaped labial plate being 

 the same. 



Both forms have been taken at Cummington, Mass., by Mr. 

 F. Knab, in a ' ; pothole " in a rock, about six feet above the level 

 of the Westfield river, in company with C. atropalpus Coq. 



