Syuipetrnm. 



71 



Difference between S, striolatum and S. vulgatum. 



The following are some of the more important points 

 ;'iven as separating these two insects : 



that are usualU' 



6^. sti-iolatiiiii. 



1. Colour more yellow. 



2. On the sides of the thorax a 



brown band, between the second 

 and third oblique black stripes. 

 V Less marked, if extended at all. 



4. ^Nlost nervures dark. 



5. The incisions of the abdominal 



segments and two very small dots 

 towards the liinder edge yellow. 

 (Male.) 



6. Absent. 



7. Vulvar scale slightly ]irominent, a 



little notched in the middle. 

 (Female.) 



8. Eighth, and ninth segments with 



black s]X)t much larger than in 

 male. (Female.) 



9. jSIid-dorsal raised line on abdomen 



yellowish. (Female.) 



^. viihzatiiui. 



1. Colour more olive. 



2. Absent. 



3. The black line on the vertex, 



containing the ocelli, extends 

 downwards on each side of the 

 tace as a margin to the eyes. 



4. Piinci|)al nervures reddish, especi- 



ally in some lights. 



5. Abdomen without yellow dots. 



6. A longitudinal black line on each 



side of the first three segments 

 of the abdomen. (Male.) 



7. \'ulvar scale very jiromineni, 



neither notched nor sinuated. 



8. Eighth and ninth segments with 



a dorsal black streak as in male. 



9. Ditto blackish. 



Oviposition, 



While ho\ering on the wing, and usually held by 

 the male per coll., the female deposits her eggs, 

 apparenth^ quite aimlessl}^ by dipping the tip of 

 her abdomen in the water. 



Egg- 

 Elliptical in section, the major axis being about 5mm. 

 (Fig. 4., No. 2). Contents granular. The eggs observed 



