274 



NEW YORK STATE MUSEUM 



tions. The head is nearly square viewed from above. The antennae 

 are rather stout, tapering uniformly and tipped with two rather 

 large tapering spines and a very short, stout remnant of a seg- 

 ment. There are also several minor conical processes. The man- 



Fig. ii Larval mandible of Psorophor a ciliata 



dibles are extremely well developed, being provided with three 

 major processes. The two ventral ones are coarsely dentate. 

 The triangular labial plate is remarkable because its 17 teeth are 

 at nearly right angles t'o the plate, the two lateral ones on each 



side being very large. The 

 comb is present on the 

 eighth segment and is re- 

 markable on account of its 

 interesting modification. 

 Its posterior border is 

 marked by a semicircle 

 of about 15 stout scales 

 with large, spatulate bases, each bearing a large, apical spine 

 and one or two smaller ones on each side. In addition, there 

 are anterior to these larger scales many smaller, beautiful, 

 platelike organs, each margined posteriorly with from about 8 to 

 over 20 fine, rather evenly set spines. The chitinous portion of 



Eig. 12 Labial plate of the larva of P s o r o 

 phora ciliata 



