Hale — Aquatic Hemiptera 411 



beyond the middle of the length of the thorax. Anterior tarsi nearly four times 

 longer than claws; intermediate tarsi more tlian four times longer than claws. 

 Abdominal gutters now prominent. Pigment on venter of abdomen dark brown. 

 Length, 4- 12 to 4-5 mm. 



Fifth instar nymph. Head much as in the adult, but notocephalon propor- 

 tionally a little Avider. The wing pads reach slightly beyond the posterior 

 margin of the thorax. Anterior tarsi rather more than four times longer than 

 the claws, intermediate tarsi more than four and a half times longer than claws. 

 The jngment on the abdomen is almost black and the streak on the underside of 

 the posterior femora is prominent ; head and prothorax dark ochraceous. 



In this instar the sex of each nymph can be determined, the immature males 

 having the eyes more prominent, the notocephalon narrower, and the inner 

 margins of the eyes rather less divergent, than in the other sex. Furthermore, by 

 means of transmitted light, the two-jointed tarsi of developing females can be 

 discerned through the integument of the single-jointed tarsi of nymphs nearing 

 the final moult (pi. xi, fig. 9) ; similarly, the monomerous anterior tarsi and 

 characteristic anterior tibiae of the male can be seen. 



$ Vertex, 1-34 to 1-8 times as wide as the synthlipsis, which is 4-5 to 6-8 

 times in the width of the head. 



9 Vertex, 1-35 to 1-5 times as wide as the synthlipsis, which is 3-4 to 4 6 

 1 imes in the width of the head. 



Length, 51 to 6 12 mm. 



The imago. Newly moulted adults have a clear whitish appearance, with 

 the underside of the abdomen brown; the scarlet of the scutellum and the dark 

 colour on pronotum and dorsum of abdomen, etc., are developed later ; the 

 integument is at first soft, and the bugs shrivel if dried too soon after the 

 metamorphosis is completed. 



S Synthlipsis, 6-97 to 9-8 times in width of head. 



9 Synthlipsis, 61 to 8 times in width of head. 



Other proportions are given in the general description of the species. 



DIMENSIONS OF NYMPHS AND ADULTS. 



