370 MONOGRAPH OF THE GENUS SYNTHEMIS, 



as in male, except — -2, a yellow dorsal line and a pair of small 

 central spots, 3-7 with bases almost completely yellow; 7 a small 

 dorsal spot; 8, variable, usually black with an anal yellow spot; 

 9, variable, usually apical two-thirds yellow; 10, black, some- 

 times with a pair of yellow spots. Ovipositor black, variable in 

 length, with segments 8-9 also vaiying in length and position 

 above it; rather short and broad, tip rounded, and carrying above 

 a small gelatinous patch of varying size. Plate vii., figs. 22a, b 

 and c, shew the variations of the end of the abdomen; fig.22J is 

 22a seen from below. Appendages 1mm., black, slender, straiglit; 

 10 projecting below in a rounded hairy tubercle. 



Var. — Besides the variation of the colouration of the end 

 abdominal segments already noted, there is, in North Queens- 

 land, a well-defined dwarf form: abdomen 32, hiiidiving 29; 

 pterostigma 2 mm.; only one row of post-trigonal cells, whereas 

 typical s|)ecimens liave one or more sets of two cells, followed by 

 single cells, after the triangle. Specimens from intermediate 

 localities shew intermediate variations. 



Types: Coll. Martin, J'9(New South Wales). 



Hab. — New South Wales and Queensland, from Illawarra to 

 Cape York. 



The series described above was taken around Sydney. 



L i f e - H i s t o r y of C hor i s thevii s j'lavoter ?n ina I a. 



The perfect insect emerges in November, and continues on the 

 wing until March or April. It is found only along densely 

 wooded creeks and rivers, and prefers swiftly running water. 

 The method of pairing and oviposition is similar to that of M. 

 guttata, but tlie eggs are not exuded in such large quantities, 

 and are pale yellowish in colour. The larva lives in the sand at 

 the bottom of the deeper pools, or under tlie sidt^s of the stream 

 where the Itank overhangs and the water is fairly deep. It 

 ■emerges by climbing up the stalks of fern and grass, often to a 

 considerable height. The full-fed nymph is very dark brown, 

 usu dly fairly clean, but less so than that of M guttata. Owing 

 to its greater villosity, particles of sand and silt often adhere to 



