102 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



vol. 37. 



Head wider than long (2 mm. : 3 mm.) and with the anterior,, 

 margin deeply excavate between the produced antero-lateral angles; 

 there is also a small median point separating the basal articles of the 

 first pair of antennae. The eyes are large, composite, wider than long, 

 and placed close to the lateral margin half way between the anterior 

 and the posterior margins. The first pair of antennas have the basal 

 article large and dilated; it extends to the end of the first article 



of the second antennas; the second and 

 third articles are narrow and subequal 

 in length; the fourth article is equal in 

 length to the second and third articles 

 taken together and extends to the end of 

 the second article of the peduncle of the 

 second pair of antennas. The second 

 antennas have the first article very short ; 

 the second is 2 mm. long; the third is 

 twice as long as the second, being 4 mm. 

 in length; the fourth is 7 mm. and the 

 fifth is 5 mm.; the flagellum is 3 mm. 

 long and is composed of five articles, the 

 first of which is twice as long as the 

 second. 



The segments of the thorax are about 

 equal in length, with the exception of 

 the fourth, which is one and a half times 

 longer than any of the others. The an- 

 terior part of the lateral margin in the 

 second, third, and fourth segments is 

 produced in a lobe on either side ; lateral 

 to these lobes the epimera are placed and 

 are in the form of narrow plates, grad- 

 ually becoming wider; on the last three 

 segments the epimera are large and con- 

 spicuous, projecting laterally and oc- 

 cupying half the margin of the fifth 

 segment, two-thirds of the margin of the 

 sixth segment, and nearly all of the margin of the seventh segment. 



The abdomen is composed of three segments, two short ones 

 anterior to the terminal segment, which is produced posteriorly to a 

 narrow rounded extremity. At the base on either side the terminal 

 segment is produced in a rounded lobe ; the incision between the lobe 

 and the rest of the segment marks a depression extending across the 

 segment, which is the indication of another coalesced segment. 

 There are four pairs of marsupial plates. 



TRITiENIA- 



FlG. 25. ARCTURUS 



tus. X 3. (Drawn by Miss 

 V. Dandridge. ) 



