l26 The $outk Ausirnlidn Naturdlisi. 



The species of Anisups have an almost perfect poise in tho 

 water when the respiratory troughs are charged with air and, 

 excepting for the deposition of eggs, rarely cling to plant 

 stems as do the larger Enithares and Notonectae. In poising 

 the post<^M-ior legs project outwards and a little forwards; 

 every few seconds they are utilised to correct the slight ten- 

 dency to automatically ascend or sink. Excepting during 

 copulation, egg-deijostioii or feeding the anterior lunbs are. 

 folded A\ liile the insects are submerged. (Fig. 1). 



For the purpose of learning the life history of Anisops 

 hyperion specimens were maintained in aquaria for eight 

 months, at the end of which time they were quite accustomed 

 to their somewhat unusual surroundings and mated. At the 

 approacli of summer, that is about the month of September^ 

 the males begin the courtship of the females, a most fascina- 

 ting procedure. A male swims below and a little behind .i 

 female, and, stridulatiiig all the time, accompanies her every 

 movemejit until she responds to his blandishments. The stri- 

 dulation is loud, and is quite easily discerned across the width 

 of a room : it may be likened to the sound of a distant grind- 

 stone at work, and is often continued intermittently 

 for the Avholc of a day. The female lays only a 

 few eggs a (hiy, the period for oviposition occupy- 

 ing about a month. As mentioned above, the eggs are 

 inserted into plant stems and loaves, a method of concealment 

 which doubtless serves as a protection against predators. 

 Wherevei" ])ossible the bug selects a moderately thick-stemmed 

 plant. When ''Water Milfoil" (Myriophylluin) and ''Pond- 

 w^eed" iPotamogeton) are present in localities w^here Anisops 

 is breeding, the stems of these plants will be found to contain 

 ova. In the aquaria the bugs were supplied with plants of 

 Potamogeton ti'icarinatus, a local water-weed, and these served 

 admiral)] y as nidi. In ovipositing the female grasps the stem 

 wdth the intermediate and anterior legs, the posterior legs re- 

 maining extended as in the swimming or poising position. 

 The surface of the plant is explored with the end of the abdo-^ 

 men, the bug walking along the stem until a suitable site is 

 selected. The ovipositor is then extruded and the drilling 

 gonapopliyses work at the stem Avith a circular, scraping 

 motion until a hole of sufficient size to accommodate an egg 

 is completed. The egg is then inserted into the prepared 

 cavity, heaving a small portion of the egg-shell exposed at the 

 mouth. J'^inally, the sensitive lip of the pygidium moves over 

 this exposed surface and the surrounding edges of the cavity 



