614 PROCEEDINGS OF THE NATIONAL MUSEUM. vou 57. 



Cerci, without consideration of the recurved part, about one-third 

 the length of the basal plate ; separately attached ; distance between 

 them about equal to their length. 



DIVISION III (pp. 614-617). 



Ocelli 3. 



10. Genus CYMATODERA Gray. 



Body robust; either digitiforni with the median abdominal seg- 

 ments only slightly wider than the preceding and succeeding ones, or 

 subclaviform ; ninth abdominal segment crescentiform or subtriangu- 

 lar; abdomen dorsally without ampullae, ventrally flattened. Chiti- 

 nous parts well developed. Membranous parts variegated; most 

 segments wdth a row of two or four orange, round spots ante- 

 rior to the scuto-scutellar suture, two on each side of median line. 

 Setae numerous in digitiform species, scarce in subclaviform species. 

 Headcapsule well sized, nearly square. Frons slightly sculptured, 

 posteriorly transversally wrinkled; endocarina posteriorly widened 

 like an arrowhead. Epicranium dorsally and ventrally with fine 

 transversal wrinkles; anterior margin of hypostoma straight, trans- 

 versal. The three ocelli large, approximately of the same size, often 

 protuberant; their position vary according to species. Length of 

 basal, second and apical antennal joints proportioned about as 2 : 1 : 1 ; 

 supplementary joint small. Mandibles about three-fourths the length 

 of frontal suture, somewhat longer than wide, length to width about 

 as 8:6; retinaculum at the middle of inner margin ; with or without 

 a low elevation between retinaculum and apex. Maxilla with band- 

 like chitinization at base of cardo and stipes ; length of basal, second, 

 and apical joints of maxillary palpus proportioned about as 1:1:1^; 

 palpiger well developed. Gula as long as frons; length of gula in 

 proportion to length of maxilla as 1 : 1^. Submentmn and mentum 

 not chitinized; stipes labii chitinized; length of basal and apical 

 joints of labial palpus about as 1 : 1|. Prothorax subrectangular, 

 as wide as long, about as long but not fully as wide as the following 

 segment; dorsally with large, moderately chitinized shield; ventrally 

 with a long, thin, subrectangular sternal plate, which in some species 

 contains on each side a round thickening just behind and similar in 

 size and form to the well chitinized presternal plates. Meso- and 

 metathorax in some speci&s with dorsal plates, the mesothoracic ones 

 being the larger; in other species no dorsal plates. Legs compara- 

 tively long, tibia more slender than femur, clawshaped tarsal joints 

 long and pointed. Abdomen with normally developed interseg- 

 mental membranes. Basal plate of cerci large, well chitinized. 

 Cerci well developed, separated or fused, hook-shaped. Spiracles 

 annuliform without any finger-shaped structures. 



